UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER
PURSUANT TO RULE 13a-16 OR 15d-16
UNDER THE SECURITIES EXCHANGE ACT OF 1934
For the month of March 1, 2021
Commission File Number 001-36487

Atlantica Sustainable Infrastructure plc
(Exact name of Registrant as specified in its charter)

Not applicable
(Translation of Registrant’s name into English)

Great West House, GW1, 17th floor
Great West Road
Brentford, TW8 9DF
United Kingdom
Tel: +44 203 499 0465

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

☒ Form 20-F |  | ☐ Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ☐
Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ☐
This Report on Form 6-K is incorporated by reference into the Registration Statement on Form F-3 of the Registrant filed with the Securities and Exchange Commission on August 6, 2018 (File 333-226611).

2020 Earnings PresentationMarch 1, 2021

DISCLAIMER Forward Looking StatementsThis presentation contains forward-looking statements. These forward-looking statements include, but are not limited to, all statements other than statements of historical facts contained in this presentation, including, without limitation, those regarding our future financial position and results of operations, our strategy, plans, objectives, goals and targets, future developments in the markets in which we operate or are seeking to operate or anticipated regulatory changes in the markets in which we operate or intend to operate. In some cases, you can identify forward-looking statements by terminology such as "aim," "anticipate," "believe," "continue," "could," "estimate," "expect," "forecast," "guidance," "intend," "is likely to," "may," "plan," "potential," "predict," "projected," "should" or "will" or the negative of such terms or other similar expressions or terminology.By their nature, forward-looking statements involve risks and uncertainties because they relate to events and depend on circumstances that may or may not occur in the future. Forward-looking statements speak only as of the date of this presentation and are not guarantees of future performance and are based on numerous assumptions. Our actual results of operations, financial condition and the development of events may differ materially from (and be more negative than) those made in, or suggested by, the forward-looking statements. Except as required by law, we do not undertake any obligation to update any forward-looking statements to reflect events or circumstances after the date hereof or to reflect the occurrence of anticipated or unanticipated events or circumstances.Investors should read the section entitled "Item 3.D—Risk Factors" and the description of our segments and business sectors in the section entitled "Item 4B. Information on the Company—Business Overview", each in our Annual Report for the fiscal year ended December 31, 2020, filed on Form 20-F, for a more complete discussion of the risks and factors that could affect us.Forward-looking statements include, but are not limited to, statements relating to: expected value, payments and closing timelines for investments; business synergies from investments; equity investment and project growth strategy; accretive investment opportunities; strategic business alternatives to ensure optimal company value; estimated returns and cash available for distribution (“CAFD”) estimates, including CAFD per share growth strategy and targets, CAFD estimates per currency, geography and sector, including as a result of project debt refinancing; net corporate leverage based on CAFD estimates; debt refinancing; ESG initiative improvement; the quality of our long-term contracts; self-amortizing project debt structure and related debt reduction; the use of non-GAAP measures as a useful predicting tool for investors; the possibility to extend asset life; cost improvements from debt refinancing; dividends; and various other factors, including those factors discussed under “Item 3.D—Risk Factors” and “Item 5.A—Operating Results” in our Annual Report for the fiscal year ended December 31, 2020 filed on Form 20-F.The CAFD and other guidance incorporated into this presentation are estimates as of March 1, 2021. These estimates are based on assumptions believed to be reasonable as of the date Atlantica published its 2020 Financial Results. Atlantica disclaims any current intention to update such guidance, except as required by law. Non-GAAP Financial Information This presentation also includes certain non-GAAP financial measures, including Adjusted EBITDA including unconsolidated affiliates, Adjusted EBITDA including unconsolidated affiliates as a percentage of revenues (margin) and CAFD. Non-GAAP financial measures are not measurements of our performance or liquidity under IFRS as issued by IASB and should not be considered alternatives to operating profit or profit for the period or any other performance measures derived in accordance with IFRS as issued by the IASB or any other generally accepted accounting principles or as alternatives to cash flow from operating, investing or financing activities. Please refer to the appendix of this presentation for a reconciliation of the non-GAAP financial measures included in this presentation to the most directly comparable financial measures prepared in accordance with IFRS as well as the reasons why management believes the use of non-GAAP financial measures (including CAFD and Adjusted EBITDA) in this presentation provides useful information to investors.In our discussion of operating results, we have included foreign exchange impacts in our revenue and Adjusted EBITDA including unconsolidated affiliates by providing constant currency growth. The constant currency presentation is not a measure recognized under IFRS and excludes the impact of fluctuations in foreign currency exchange rates. We believe providing constant currency information provides valuable supplemental information regarding our results of operations. We calculate constant currency amounts by converting our current period local currency revenue and Adjusted EBITDA using the prior period foreign currency average exchange rates and comparing these adjusted amounts to our prior period reported results. This calculation may differ from similarly titled measures used by others and, accordingly, the constant currency presentation is not meant to substitute for recorded amounts presented in conformity with IFRS as issued by the IASB nor should such amounts be considered in isolation.

Key Messages +$300M in equity investments closed in 2020 ~$280M new equity investments already agreed for 20212 Mid-term CAFD per share growth target set at 5-8% $200.7 million CAFD in 2020, 5.5% year-over-year growth CAFD per share calculated using the number of shares as of March 1, 2021.See page 15 for further details. Strong ESG Ratings 2021 CAFD target guidance established at $220M-$240M ($1.99-$2.17 per share1)

Sustainable Infrastructure 1. Financial Results

US $ in millions 2020 2019 ∆ Reported Revenue 1,013.3 1,011.5 0.2% Adjusted EBITDA incl. unconsolidated affiliates1 796.1 821.6 (3.1)% Margin2 79% 81% CAFD 200.7 190.3 +5.5% 216 Additional Cash Generation from project debt refinancings in the period Adjusted EBITDA including unconsolidated affiliates includes our share in EBITDA of unconsolidated affiliates (see reconciliation on page 37).Adjusted EBITDA Margin including unconsolidated affiliates is defined as Adjusted EBITDA including unconsolidated affiliates divided by revenue (see reconciliation on page 39).

HIGHLIGHTSStrong Cash Flow Generation 2020. Million USD. Amounts obtained from our annual consolidated financial statements for the year ended December 31, 2020, and from the reconciliation presented in page 37.

WATER 2020 2019 ∆ 43.1 24.6 +75% 31.5 22.6 +39% 73% 92% RENEWABLES 2020 2019 ∆ 753.1 761.1 (1)% 576.3 604.1 (5)% 77% 79% EFFICIENT NATURAL GAS 2020 2019 ∆ 111.0 122.3 (9)% 101.0 109.2 (8)% 91% 89% TRANSMISSION& TRANSPORT. 2020 2019 ∆ 106.1 103.5 +3% 87.3 85.7 +2% 82% 83% By Sector US $ in millions Revenue Adjusted EBITDA incl. unconsolidated affiliates1 Margin2 EMEA NORTH AMERICA 2020 2019 ∆ 330.9 333.0 (1)% 279.4 307.2 (9)% 84% 92% SOUTH AMERICA 2020 2019 ∆ 530.9 536.3 (1)% 396.7 399.0 (1)% 75% 74% By Region US $ in millions Revenue Adjusted EBITDA incl. unconsolidated affiliates1 Margin2 Adjusted EBITDA including unconsolidated affiliates includes our share in EBITDA of unconsolidated affiliates (see reconciliation on page 37).Adjusted EBITDA Margin including unconsolidated affiliates is defined as Adjusted EBITDA including unconsolidated affiliates divided by revenue (see reconciliation on page 39). 2020 2019 ∆ 151.5 142.2 +7% 120.0 115.3 +4% 79% 81% HIGHLIGHTSPerformance by Sector and Region

Includes curtailment in wind assets for which we receive compensation.Represents total installed capacity in assets owned or consolidated at the end of the year, regardless of our percentage of ownership in each of the assets.Major maintenance overhaul held in Q1 and Q2 2019 in ACT, as scheduled, which reduced production and electric availability as per the contract. GWh produced includes 30% of the production from Monterrey since August 2, 2019.Availability refers to the time during which the asset was available to our client totally or partially divided by contracted or budgeted availability, as applicable.Includes 43MW corresponding to our 30% share in Monterrey since August 2, 2019. WATER RENEWABLES TRANSMISSION & TRANSPORTATION EFFICIENT NATURAL GAS 2020 2019 Availability4 100.1% 101.2% Mft3 in operation2 17.5 10.5 2020 2019 GWh produced1 3,244 3,236 MW in operation2 1,551 1,496 2020 2019 GWh produced3 2,574 2,090 Availability3,4 102.1% 95.0% MW in operation5 343 343 2020 2019 Availability4 100.0% 100.0% Miles in operation 1,166 1,166 KEY OPERATIONAL METRICSSteady Operational Performance

Adjusted EBITDA including unconsolidated affiliates includes our share in EBITDA of unconsolidated affiliates (see reconciliation on page 37).Includes proceeds for $3.3 million and $22.2 million in 2020 and 2019 respectively, related to the amounts received by Solana in relation to the consent with the DOE. Consolidated cash as of December 31, 2020 increased by $305.7 million vs December 31, 2019 including FX translation differences of $10.7 million. US $ in millions 2020 2019 Adjusted EBITDA incl. unconsolidated affiliates1 796.1 821.6 Share in Adjusted EBITDA of unconsolidated affiliates (14.5) (10.4) Net interest and income tax paid (287.2) (299.5) Variations in working capital (33.2) (113.4) Non-monetary adjustments and other (23.0) (34.7) OPERATING CASH FLOW 438.2 363.6 INVESTING CASH FLOW2 (5.9) (118.2) FINANCING CASH FLOW (137.3) (310.2) Net change in consolidated cash3 295.0 (64.8) CASH FLOWOperating Cash Flow +20.5%

NET DEBT POSITION1 Net debt corresponds to gross debt including accrued interest less cash and cash equivalents.Corporate Net Debt defined as indebtedness where Atlantica Sustainable Infrastructure plc. is the primary obligor minus cash and cash equivalents held at Atlantica Sustainable Infrastructure plc. Project Net Debt is defined as indebtedness where one of our subsidiaries is the primary obligor minus cash and cash equivalents held by one of our subsidiaries.Net corporate leverage calculated as corporate net debt divided by 2020 CAFD before corporate debt service. US $ in millions As of Dec. 31,2020 As of Dec. 31,2019 Corporate Net Debt2 658.5 657.8 Project Net Debt3 4,704.3 4,355.6 NET DEBTCorporate Leverage Corporate net debt / CAFD pre corporate debt service4 3.0x 2.8x

Support local communities during COVID-19Issued a Board Diversity Policy2 of 4 Board committees chaired by womenIncluded in Bloomberg Gender Equality Index 87.5% EBITDA from low carbon footprint assetsMaintained very low GHG Emissions: 0.17 CO2/MWh 5.4 million of tons of CO2 avoided (vs. 4.7 in 2020)3Carbon pricing to evaluate investments Occupational Health and Safety Continued improvement in our main KPIs:1.0 TRIR1 (vs. 1.2 in 2019)0.3 LTIR2 (vs. 0.3 in 2019)Committed to maintaining a zero- accident culture Occupational Health and Safety Majority of Independent Directors with diverse perspectives and expertiseBoard committees comprised only by independent membersNew ESG-related policies Total Recordable Incident Rate (TRIR) represents the total number of recordable accidents with and without leave (lost time injury) recorded in the last 12 months per 200,000 worked hours.Lost Time Injury Rate (LTIR) represents the total number of recordable accidents with leave (lost time injury) recorded in the last 12 months per 200,000 worked hours. Calculated considering GHG emissions Scope 1 and 2 and energy generation of our power generation assets, both electric and thermal energy. The GHG Equivalences Calculator uses the Avoided Emissions and Generation Tool (AVERT) U.S. national weighted average CO2 marginal emissions rate to convert reductions of Kilowatt-hours into avoided units of carbon dioxide emissions. Climate Change and GHG Emissions Diversity and Community Engagement Corporate Governance ESG FOCUSFocused on ESG Priorities

ESG FOCUSStrong ESG Ratings in 2021 Renewable Power Production #1 out of 67 Utilities #1 out of 574 Global Universe #21 out of 13,568 Risk score of 7.6, improved versus 2020“Negligible risk of experiencing material financial impacts” 1 from ESG factors“Strong management of material ESG issues”1 “Leadership: Implementing current best practices”1 #1 Globally in Renewable Power and Utilities (ESG Risk Rating) “A-” Rating 100 Most Sustainable Corporations in the World 12th Globally, 2nd in Power According to Sustainalytics ESG Risk Rating Summary Report dated February 22, 2021 and CDP Score Report - Climate Change 2020. For further information please see both reports on our website. Feb. 2021 Jan. 2021 Jan. 2021

Sustainable Infrastructure Sustainable Infrastructure 2. 2021 Outlook

2020 HIGHLIGHTSOver $300M in Investments Closed in 2020 ü Solana tax equity investor buyout1 $290M ü Chile PV 1 acquisition through the Renewable Energy Platform $4M ü Others (Ten West Link, Tenes) $8M $302M Total Equity Investments Total equity investment is expected to be up to $290 million of which $272 million has already been paid.

2021 INVESTMENTSApprox. $280M Agreed by Q1 2021 ~$280MTotal $170M1 $20M $20M $50M $20M Total investment is expected to be approximately $170 million, including approximately $130 million in equity value and $40 million expected to be invested in reducing project debt.

2021 INVESTMENTSCoso Increases presence in Renewables in the USContracted revenues~19 years average PPA lifeTerminal value post PPA Acquisition of a 135 MW Contracted Renewable Energy Plant in California Third largest geothermal plant in the USProven track record, in-house O&M and asset managementProvides baseload renewable energy to the California ISOClosing expected in H1 2021$170 million investment1 INVESTMENT HIGHLIGHTS Investment grade offtakers12.4x EV/EBITDASynergies with existing assets in the Southwest Total investment is expected to be approximately $170 million, including approximately $130 million in equity value and $40 million expected to be invested in reducing project debt.

La Sierpe, PV asset in Colombia to be Acquired from Algonquin 2 Agreement with Algonquin to potentially co-invest in 2 additional assets in Colombia with ~30 MW combined capacity ~20 MW solar plant In construction by AAGES, Algonquin’s international Joint Venture ~$20M expected equity investment15-year PPA in placeClosing after COD, expected by mid-2021 2021 INVESTMENTSCalgary District Heating, La Sierpe and Chile PV 2 Calgary District Heating 1 3 Chile PV 2 OECD Investment Grade countryAttractive growth prospects for renewables First Investment in Colombia

Dividends Paid1 - US$ per share Sum of the dividends per share paid to shareholders in each quarter of the year. DIVIDENDGrowing Dividend Per Share

820 220 860 240 2021 TARGETS2021E Target Guidance 2021E Guidance1 Range in $ Millions Adjusted EBITDA incl. unconsolidated affiliates Assumes the closing of the acquisitions previously announced and contributions from investments not yet disclosed. See “Disclaimer – Forward Looking Statements”. See reconciliation of 2021E Guidance on page 40. CAFD - -

Growth Beyond 2021

40 100 150 Construction of new assets, in many cases co-investing with partners.Early-stage 1GW development pipeline in renewables Organic Development 1 2 Third Party Acquisitions Expansion of assets 20 30 30 50 50 50 2021E 2022E 2023E Invest in existing assets MID-TERM TARGETS$300M Equity Investment per Year Smaller proprietary situations 190 120 70 Competitive processes Total >300 300 300 Note: Targeted equity investments shown above are estimates. These targeted equity investments are subject to change depending on the different circumstances such as, but not limited to, project opportunities, timing, status of negotiations, access to capital markets, etc. The targeted equity investments may vary from category to category depending on such circumstances. Atlantica does not undertake any obligation to update any forward-looking statements to reflect events or circumstances after the date hereof or to reflect the occurrence of anticipated or unanticipated events or circumstances. Atlantica does not guarantee the timing nor size of the investments or if it will make any investments at all. Also, the projects and capacities represented in this slide are estimates. They include early-stage projects, projects in which we participate with other partners and projects under our ROFO Agreements. Development activities always involve a rate of failure. We cannot guarantee that any of these projects will materialize. 3

Organic Escalation factorsOperational improvementsExpansion of existing assetsInvest more in existing assets (i.e., over $400M with partners) 2-3% Development Partnerships:AAGES/ AlgonquinOther partnersIn-house 2-3% MID-TERM TARGETSOur Growth Strategy 1 2 Third Party Acquisitions 1-2% Smaller proprietary situationsBilateral/ Competitive processes CAFD per share Growth Target until 2024 5-8% 3 Note: Atlantica has targeted a CAFD per share Compound Annual Growth Rate in the range of 5% to 8% in the upcoming 4 years, from the fourth quarter of 2020 until the year 2024.

Sustainable Infrastructure Update pics 4. Appendix

LIQUIDITY AND DEBT MATURITIES SUMMARYHealthy Balance Sheet and Strong Liquidity Strong Liquidity and No Significant Corporate Debt Maturities in the Short-term >$750 million @ 31/12/20 Corporate Liquidity ~5.1 years average maturity1 of current corporate debt RCF’s maturity in December 2022. Total limit of $425.0 million, of which $415.0 million are available as of Dec. 31, 2020~$750 million available liquidity, out of which $335.2 million is corporate cash as of Dec. 31, 2020 Corporate Debt Maturities1 Corporate Debt Maturites as of December 31, 2020, presented for their accounting amounts. 2 2

CORPORATE DEBT DETAILSCorporate Debt as of December 31, 2020No significant maturities in the short term Exchange rates as of December 31, 2020 (EUR/USD = 1.2216).Amounts include principal amounts outstanding, unless stated otherwise.As of December 31, 2020, there was no amount drawn from our RCF. Total RCF limit of $425 million with $415 million available.Other facilities include the commercial paper program issued in October 2020, accrued interest payable and other debts. US $ in millions1 Maturity Amounts2 Credit Facilities (Revolving CF)3 2022 - (Other facilities)4 2021 – 2025 29.7 2019 NIFA5(€ denominated) 2025 344.0 Green Exchangeable Bond6 2025 102.1 Green Senior Secured Notes 2026 351.0 2020 NIFA7 (€ denominated) 2027 166.9 Total 993.7 (5) 2019 NIFA means Note Issuance Facility Agreement. 2019 NIFA refers to the senior unsecured note facility dated April 30, 2019, of Euro equivalent of $300 million.(6) Senior unsecured notes dated July 17, 2020, exchangeable into ordinary shares of Atlantica, cash, or a combination of both, at Atlantica’s election.(7) 2020 NIFA refers to the senior unsecured note financing dated July 8, 2020, of €140 million.

Includes cash classified in short-term financial investments as of December 31, 2019. Exchange rates as of December 31, 2020 (EUR/USD = 1.2216) and December 31, 2019 (EUR/USD = 1.1213).Restricted cash is cash which is restricted generally due to requirements of project finance lenders. US $ in millions2 As of Dec. 312020 As of Dec. 312019 Corporate cash at Atlantica 335.2 66.0 Existing available revolver capacity 415.0 341.0 Total Corporate Liquidity 750.2 407.0 Cash at project companies1 533.3 531.5 - Restricted3 279.8 373.6 - Other 253.5 157.9 LIQUIDITYLiquidity Position1

Total cash obtained from non-recourse project financings and refinancings to be used in potential acquisitions: Additional tranche of debt at the SPV with a private investor3.0% interest costBack-ended amortization with a 15 year maturity Helioenergy New Project Debt 2 $43M New debt in a holding of certain Spanish assets3.1% interest cost75% bullet in year 5 / 25% amortizing Green Project Finance in Spain closed in Q2 3 $143M Approx. Net Recap1 $216M New approx. €326 million project debt to replace the previous one (approx. €250 million outstanding) and cancel legacy swapsCost improvement: 1.9% interest cost vs. ~4.2% in the previous financing (with spread step-ups)Maturity extension: 17 year maturity vs. 7 year in the previous financing $30M Helios Refinancing After refinancing fees and costs and swap cancelation in the case of Helios. GROWTH STRATEGYProject Debt RefinancingsAdditional cash for acquisitions without increasing Corporate Debt 1

Weighted Average Life Project debt term Represents weighted average years remaining as of December 31, 2020. (2) Regulation term in the case of Spain and Chile TL3. PPAs with predefined prices for ~17 years on average1 Refinancing opportunities could increase CAFD in earlier years Possibility to extend life in many assets (excluding ATN and ATS) Tails in most assets after debt amortization Contract term2 LONG-TERM STABLE CASH FLOWPortfolio of Assets

Key principle: non-recourse project financing in ring-fenced subsidiaries100% project debt self-amortizing progressively before the end of the contracted lifeLow interest rate risk, with +90% of interest rates fixed or hedged ~$1.9B planned debt reduction in the next 5 years FINANCING Self-Amortizing Project Debt Structure1 Project debt amortization schedule as of December 31, 2020.

2018 1Q19 2Q19 3Q19 4Q19 2019 1Q20 2Q20 3Q20 4Q20 2020 Revenues 1,043,822 221,452 283,338 293,373 213,289 1,011,452 210,403 255,344 302,987 244,526 1,013,260 Adj. EBITDA incl. unconsolidated affiliates 858,717 181,106 229,352 247,668 163,429 821,555 165,962 214,107 240,958 175,096 796,123 Adj. EBITDA margin (%) 82.3% 81.8% 80.9% 84.4% 76.6% 81.2% 78.9% 83.9% 79.5% 71.6% 78.6% Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates (8,110) (2,017) (2,043) (3,062) (3,229) (10,351) (3,553) (3,959) (3,943) (3,013) (14,468) Adjusted EBITDA 850,607 179,089 227,309 244,606 160,200 811,204 162,409 210,148 237,015 172,083 781,655 Dividends from unconsolidated affiliates 4,432 - - 26,945 3,498 30,443 5,120 5,262 9,758 2,106 22,246 Non-monetary items (99,280) (14,632) (7,729) (10,288) (4,783) (37,432) (4,334) (3,683) (5,327) (8,289) (21,633) Net interest and income tax paid (333,537) (13,925) (129,405) (24,339) (131,845) (299,514) (11,436) (119,517) (31,625) (124,661) (287,239) Principal amortization of indebtedness net of new indebtedness at projects (229,647) (15,176) (93,935) (22,115) (123,568) (254,794) (14,898) (75,301) (18,963) (151,260) (260,422) Deposits into/withdrawals from debt service accounts4 (41,197) 21,461 25,564 (52,463) 4,721 (717) 32,921 17,605 8,844 27,807 87,177 Change in non-restricted cash at project companies4 22,352 (61,445) 69,866 (58,847) 119,707 69,281 (50,467) 31,257 (94,192) 34,784 (78,618) Dividends paid to non-controlling interests (9,745) - (5,105) (18,978) (5,156) (29,239) (4,915) (9,246) (6,833) (1,950) (22,944) Changes in other assets and liabilities 7,562 (50,253) (37,183) (38,792) 27,271 (98,957) (66,842) (6,808) (46,724) 100,843 (19,531) Cash Available For Distribution (CAFD) 171,547 45,119 49,382 45,729 50,045 190,275 47,558 49,717 51,953 51,463 200,691 Dividends declared1 139,302 39,625 40,641 41,657 41,657 163,579 41,657 42,673 42,673 46,491 173,494 # of shares2 100,217,260 100,217,260 101,601,662 101,601,662 101,601,662 101,601,662 101,601,662 101,601,662 101,601,662 110,691,722 n/a DPS (in $ per share) 1.39 0.39 0.40 0.41 0.41 1.61 0.41 0.42 0.42 0.42 1.67 Project debt 5,091.1 5,076.4 4,997.4 4,931.3 4,852.3 4,852.3 4,777.2 5,007.6 5,281.2 5,237.6 5,237.6 Project cash (524.8) (546.7) (469.0) (568.5) (496.8) (496.8) (535.3) (510.1) (602.2) (533.3) (533.3) Net project debt 4,566.3 4,529.6 4,528.4 4,362.8 4,355.6 4,355.6 4,241.9 4,497.5 4,679.0 4,704.3 4,704.3 Corporate debt 684.1 697.5 689.6 686.4 723.8 723.8 807.3 837.0 959.7 993.7 993.7 Corporate cash (106.7) (107.9) (107.0) (73.2) (66.0) (66.0) (154.9) (278.7) (186.7) (335.2) (335.2) Net corporate debt 577.4 589.7 582.6 613.2 657.8 657.8 652.4 558.3 773.0 658.5 658.5 Total net debt 5,143.6 5.119.3 5,111.0 4,976.0 5,013.3 5,013.3 4,894.4 5,055.8 5,452.0 5,362.9 5,362.8 Net Corporate Debt/CAFD pre corporate interests3 2.7x 2.5x 2.5x 2.7x 2.9x 2.9x 2.4x 2.3x 3.3x 3.0x 3.0x HISTORICAL FINANCIAL REVIEWKey Financials by Quarter Debt details Key Financials US $ in thousands Dividends are paid to shareholders in the quarter after they are declared.Number of shares outstanding on the record date corresponding to each dividend.Ratios presented are the ratios shown on each earnings presentation. (4) “Deposits into/ withdrawals from restricted accounts” and “Change in non-restricted cash at project level” are calculated on a constant currency basis to reflect actual cash movements isolated from the impact of variations generated by foreign exchange changes during the period. Prior periods have been recalculated to conform this presentation. US $ in millions

HISTORICAL FINANCIAL REVIEWSegment Financials by Quarter 2 2018 1Q19 2Q19 3Q19 4Q19 2019 1Q20 2Q20 3Q20 4Q20 2020 by Geography NORTH AMERICA 357,177 60,441 104,095 109,378 59,052 332,965 59,283 98,648 109,757 63,233 330,921 SOUTH AMERICA 123,214 33,493 35,597 36,671 36,447 142,207 35,654 39,375 36,990 39,441 151,460 EMEA 563,431 127,518 143,646 147,325 117,790 536,280 115,466 117,321 156,240 141,852 530,879 by Business Sector RENEWABLES 793,557 156,817 223,269 229,742 151,261 761,090 150,793 193,881 234,556 173,859 753,089 EFFICIENT NAT. GAS 130,799 34,009 27,689 31,193 29,390 122,281 26,403 25,629 28,086 30,912 111,030 TRANSMISSION & TRANSP. 95,998 24,867 26,231 25,926 26,429 103,453 26,608 26,787 25,834 26,813 106,042 WATER 23,468 5,759 6,149 6,511 6,209 24,629 6,599 9,047 14,511 12,942 43,099 Total Revenue 1,043,822 221,452 283,338 293,373 213,289 1,011,452 210,403 255,344 302,987 244,526 1,013,260 2018 1Q19 2Q19 3Q19 4Q19 2019 1Q20 2Q20 3Q20 4Q20 2020 by Geography NORTH AMERICA 308,748 50,870 96,293 108,198 51,881 307,242 52,661 89,954 95,879 40,871 279,365 86.4% 84.2% 92.5% 98.9% 88.8% 92.3% 88.8% 91.2% 87.4% 64.6% 84.4% SOUTH AMERICA1 100,233 28,212 29,252 30,293 27,589 115,346 28,422 31,380 29,947 30,275 120,024 81.3% 84.2% 82.2% 82.6% 75.6% 81.1% 79.7% 79.7% 81.0% 76.8% 79.2% EMEA 449,736 102,024 103,807 109,177 83,959 398,968 84,879 92,773 115,132 103,950 396,734 79.8% 80.0% 72.3% 74.1% 71.3% 74.4% 73.5% 79.1% 73.7% 73.3% 74.7% by Business Sector RENEWABLES 664,429 123,484 177,910 192,168 110,517 604,079 113,670 161,415 181,788 119,412 576,285 83.7% 78.7% 79.7% 83.6% 73.1% 79.4% 75.4% 83.3% 77.5% 68.7% 76.5% EFFICIENT NAT. GAS 93,858 30,476 23,826 27,983 26,915 109,200 24,462 23,303 27,479 25,762 101,006 71.8% 89.6% 86.1% 89.7% 91.6% 89.3% 92.6% 90.9% 97.8% 83.3% 91.0% TRANSMISSION & TRANSP. 78,463 21,650 21,936 21,548 20,524 85,658 21,922 22,423 21,702 21,225 87,272 81.7% 87.1% 83.6% 83.1% 77.6% 82.7% 82.4% 83.7% 84.0% 79.2% 82.3% WATER 21,967 5,496 5,680 5,969 5,473 22,619 5,908 6,966 9,989 8,697 31,560 93.6% 95.4% 92.4% 91.7% 88.1% 91.8% 89.5% 77.0% 68.8% 67.2% 73.2% Total Adj. EBITDA incl. unconsolidated affiliates1 858,717 181,106 229,352 247,668 163,429 821,556 165,962 214,107 240,958 175,096 796,123 82.3% 81.8% 80.9% 84.4% 76.6% 81.2% 78.9% 83.9% 79,5% 71.6% 78.6% Revenue Adj. EBITDA incl. unconsolidated affiliates Adjusted EBITDA includes our share in EBITDA of unconsolidated affiliates. US $ in thousands

2018 1Q19 2Q19 3Q19 4Q19 2019 1Q20 2Q20 3Q20 4Q20 2020 RENEWABLES3 (GWh) 3,058 581 1,071 1,048 536 3,236 526 957 1,125 636 3,244 (GWh) 2,318 383 483 615 694 2,090 644 624 664 642 2,574 (availability %) 99.8% 87.1% 89.9% 101.5% 101.4% 95.0% 102.4% 100.9% 103.8% 101.2% 102.1% TRANSMISSION & TRANSP. (availab.%) 99.9% 99.9% 100.0% 99.9% 100.0% 100.0% 99.9% 99.9% 100.0% 100.0% 100.0% WATER (availability %) 102.0% 99.8% 100.6% 103.6% 100.1% 101.2% 101.8% 102.2% 101.1% 95.4% 100.1% 2018 1Q19 2Q19 3Q19 4Q19 2019 1Q20 2Q20 3Q20 4Q20 2020 RENEWABLES1 (MW) 1,496 1,496 1,496 1,496 1,496 1,496 1,496 1,551 1,551 1,551 1,551 EFF. NATURAL GAS2 (electric MW) 300 300 300 343 343 343 343 343 343 343 343 TRANSMISSION & TRANSP. (Miles) 1,152 1,152 1,152 1,152 1,166 1,166 1,166 1,166 1,166 1,166 1,166 WATER1 (Mft3/day) 10.5 10.5 10.5 10.5 10.5 10.5 10.5 17.5 17.5 17.5 17.5 Capacity in operation(at the end of the period) Production / Availability 5 5 5 Represents total installed capacity in assets owned or consolidated at the end of the year, regardless of our percentage of ownership in each of the assets.Includes 43 MW corresponding to our 30% share in Monterrey since August 2, 2019.Includes curtailment in wind assets for which we receive compensation.Major maintenance overhaul held in Q1 and Q2 2019 in ACT, as scheduled, which reduced production and electric availability as per the contract. GWh produced includes 30% of the production from Monterrey since August 2, 2019.Availability refers to the time during which the asset was available to our client totally or partially divided by contracted or budgeted availability, as applicable. EFFICIENT NATURAL GAS4 HISTORICAL FINANCIAL REVIEWKey Performance Indicators

2018 1Q19 2Q19 3Q19 4Q19 2019 1Q20 2Q20 3Q20 4Q20 2020 US 28.2% 15.2% 39.8% 35.2% 16.3% 26.6% 18.2% 37.5% 35.2% 17.6% 27.1% Spain 16.9% 12.1% 26.7% 27.2% 6.7% 18.2% 8.0% 22.1% 28.6% 8.3% 16.8% Kaxu 36.0% 48.7% 27.8% 27.5% 45.4% 37.3% 28.9% 8.6% 26.8% 44.7% 27.3% WIND2 Uruguay 37.2% 33.0% 36.3% 40.9% 38.0% 37.2% 34.6% 40.8% 40.6% 42.8% 39.7% SOLAR Historical Capacity Factors1 Capacity factor ratio represents actual electrical energy output over a given period of time to the maximum possible electrical energy output assuming continuous operation at full nameplate capacity over that period. Historical Capacity Factors are calculated from the date of entry into operation or the acquisition of each asset. Some capacity factors are not indicative of a full period of operations.Includes curtailment production in wind assets for which we receive compensation. HISTORICAL FINANCIAL REVIEWCapacity Factors

CURRENCY2 SECTOR GEOGRAPHY Based on CAFD estimates for the 2021-2025 period, including the acquisitions announced. See “Disclaimer – Forward Looking Statements”.Including the effect of currency swap agreements. of long-term interest rates in projects are fixed or hedged2 ~ 90% 90 Denominatedin USD % > 72% Renewable14% Efficient Natural Gas11% Transmission & Transport. 3% Water 41% North America36% Europe14% South America 9% RoW SIZEABLE AND DIVERSIFIED ASSET PORTFOLIOPortfolio Breakdown Based on Estimated CAFD1 69% Renewable15% Transmission & Transport.13% Efficient Natural Gas 3% Water 45% North America35% Europe12% South America8% RoW Dec-2019:

As of March 1, 2021 ASSET TYPE STAKE LOCATION GROSSCAPACITY OFFTAKER RATING 1 YEARS INCONTRACT LEFT CURRENCY RENEWABLE ENERGY Solana 100% USA (Arizona) 280 MW APS A-/A2/A- 23 USD Mojave 100% USA (California) 280 MW PG&E BB-/WR/BB 19 USD Solaben 2/3 70% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 17/17 EUR 3 Solacor 1/2 87% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 16/16 EUR 3 PS 10/20 100% Spain 31 MW Kingdom of Spain A/Baa1/A- 11/13 EUR 3 Helioenergy 1/2 100% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 16/16 EUR 3 Helios 1/2 100% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 16/17 EUR 3 Solnova 1/3/4 100% Spain 3x50 MW Kingdom of Spain A/Baa1/A- 14/14/15 EUR 3 Solaben 1/6 100% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 18/18 EUR 3 Seville PV 80% Spain 1 MW Kingdom of Spain A/Baa1/A- 15 EUR Kaxu 51% South Africa 100 MW Eskom BB/Ba2/BB-2 14 ZAR Chile PV 1 35% Chile 55 MW n/a n/a n/a USD 4 Chile PV 2 35% Chile 40 MW n/a n/a n/a USD 4 Palmatir 100% Uruguay 50 MW UTE BBB/Baa2/BBB-2 13 USD Cadonal 100% Uruguay 50 MW UTE BBB/Baa2/BBB-2 14 USD Melowind 100% Uruguay 50 MW UTE BBB/Baa2/BBB-2 15 USD Mini-Hydro 100% Peru 4 MW Peru BBB+/A3/BBB+ 12 USD EFFICIENT NATURAL GAS ACT 100% Mexico 300 MW Pemex BBB/Ba2/BB- 12 USD 4 Monterrey 30% Mexico 142 MW Industrial Customers Not rated 18 USD 4 TRANSMISSION & TRANSPORT. ATN 100% Peru 379 miles Peru BBB+/A3/BBB+ 20 USD 4 ATS 100% Peru 569 miles Peru BBB+/A3/BBB+ 23 USD 4 ATN 2 100% Peru 81 miles Minera Las Bambas Not rated 12 USD 4 Quadra 1/2 100% Chile 49 miles / 32 miles Sierra Gorda Not rated 14/14 USD 4 Palmucho 100% Chile 6 miles Enel Generacion Chile BBB+/Baa1 /A- 17 USD 4 Chile TL3 100% Chile 50 miles CNE A+/A1/A- Regulated USD 4 WATER Skikda 34% Algeria 3.5 Mft3/day Sonatrach & ADE Not rated 13 USD 4 Honaine 26% Algeria 7 Mft3/day Sonatrach & ADE Not rated 17 USD 4 Tenes 51% Algeria 7 Mft3/day Sonatrach & ADE Not rated 19 USD 4 Reflects the counterparties’ issuer credit ratings issued by S&P, Moody’s and Fitch, respectively, as of February 26, 2021.For Kaxu, it refers to the credit rating of the Republic of South Africa, and for Palmatir, Cadonal and Melowind, it refers to the credit rating of Uruguay, as UTE is unrated.Gross cash in euros dollarized through currency hedges.USD denominated but payable in local currency. AT A GLANCESizeable and Diversified Asset Portfolio

NON-GAAP FINANCIAL INFORMATIONReconciliation of Non-GAAP Measures Our management believes Adjusted EBITDA including unconsolidated affiliates and CAFD are useful to investors and other users of our financial statements in evaluating our operating performance because it provides them with an additional tool to compare business performance across companies and across periods. Adjusted EBITDA is widely used by investors to measure a company’s operating performance without regard to items such as interest expense, taxes, depreciation and amortization, which can vary substantially from company to company depending upon accounting methods and book value of assets, capital structure and the method by which assets were acquired. Our management believes CAFD is a relevant supplemental measure of the Company’s ability to earn and distribute cash returns to investors and is useful to investors in evaluating our operating performance because securities analysts and other interested parties use such calculations as a measure of our ability to make quarterly distributions. In addition, CAFD is used by our management team for determining future acquisitions and managing our growth. Adjusted EBITDA and CAFD are widely used by other companies in the same industry. Our management uses Adjusted EBITDA and CAFD as measures of operating performance to assist in comparing performance from period to period on a consistent basis. They also readily view operating trends as a measure for planning and forecasting overall expectations, for evaluating actual results against such expectations, and for communicating with our board of directors, shareholders, creditors, analysts and investors concerning our financial performance.We present non-GAAP financial measures because we believe that they and other similar measures are widely used by certain investors, securities analysts and other interested parties as supplemental measures of performance and liquidity. The non-GAAP financial measures may not be comparable to other similarly titled measures employed by other companies and they may have limitations as analytical tools. These measures may not be fit for isolated consideration or as a substitute for analysis of our operating results as reported under IFRS as issued by the IASB. Non-GAAP financial measures and ratios are not measurements of our performance or liquidity under IFRS as issued by the IASB. Thus, they should not be considered as alternatives to operating profit, profit for the period, any other performance measures derived in accordance with IFRS as issued by the IASB, any other generally accepted accounting principles or as alternatives to cash flow from operating, investing or financing activities. Some of the limitations of these non-GAAP measures are:they do not reflect our cash expenditures, future requirements for capital expenditures or contractual commitments; they do not reflect changes in, or cash requirements for, our working capital needs;they may not reflect the significant interest expense, or the cash requirements necessary, to service interest or principal payments, on our debts;although depreciation and amortization are non-cash charges, the assets being depreciated and amortized will often need to be replaced in the future and Adjusted EBITDA and CAFD do not reflect any cash requirements that would be required for such replacements;some of the exceptional items that we eliminate in calculating Adjusted EBITDA reflect cash payments that were made, or will be made in the future; andthe fact that other companies in our industry may calculate Adjusted EBITDA and CAFD differently than we do, which limits their usefulness as comparative measures.

RECONCILIATIONReconciliation of Cash Available For Distribution and Adjusted EBITDA to Profit for the period attributable to the Company Adjusted EBITDA including unconsolidated affiliates includes our share in EBITDA of unconsolidated affiliates.“Deposits into/ withdrawals from restricted accounts” and “Change in non-restricted cash at project level” are calculated on a constant currency basis to reflect actual cash movements isolated from the impact of variations generated by foreign exchange changes during the period. Prior period has been recalculated to conform this presentation. (in thousands of U.S. dollars) For the three-month period ended December 31, For the twelve-month period ended December 31, 2020 2019 2020 2019 Profit/(loss) for the period attributable to the Company $ (49,241) $ 1,303 $ 11,968 $ 62,135 Profit/(loss) attributable to non-controlling interest 7,948 4,925 4,906 12,473 Income tax (202) (16,029) 24,877 30,950 Share of loss/(profit) of associates carried under the equity method (2,758) (3,576) (510) (7,457) Financial expense, net 109,899 97,711 331,810 402,348 Operating profit $ 65,646 $ 84,334 $ 373,051 $ 500,449 Depreciation, amortization, and impairment charges 106,438 75,866 408,604 310,755 Adjusted EBITDA $ 172,083 $ 160,200 $ 781,655 $ 811,204 Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates 3,013 3,229 14,468 10,351 Adjusted EBITDA including unconsolidated affiliates1 $ 175,096 $ 163,429 $ 796,123 $ 821,555 Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates (3,013) (3,229) (14,468) (10,351) Dividends from equity method investments 2,106 3,498 22,246 30,443 Non-monetary items (8,289) (4,783) (21,633) (37,432) Net interest and income tax paid (124,661) (131,845) (287,239) (299,514) Deposits into/ withdrawals from restricted accounts 27,807 (1,692) 87,177 1,719 Change in non-restricted cash at project level 34,784 115,626 (78,618) 70,527 Dividends paid to non-controlling interests (1,950) (5,156) (22,944) (29,239) Changes in other assets and liabilities 100,843 37,765 (19,531) (102,639) Cash Available For Distribution before Debt Principal Repayments 202,723 173,613 461,113 445,069 Principal amortization of indebtedness (151,260) (123,568) (260,422) (254,794) Cash Available For Distribution $ 51,463 $ 50,045 $ 200,691 $ 190,275

RECONCILIATIONReconciliation of Adjusted EBITDA including unconsolidated affiliates to Net Cash Provided by Operating Activities Adjusted EBITDA including unconsolidated affiliates includes our share in EBITDA of unconsolidated affiliates. (in thousands of U.S. dollars) For the three-month period ended December 31, For the twelve-month period ended December 31, 2020 2019 2020 2019 Net cash provided by operating activities $ 134,978 $ 42,145 $ 438,221 $ 363,581 Net interest and income tax paid 124,661 131,845 287,239 299,514 Variations in working capital (95,713) (18,699) 33,212 113,351 Other non-cash adjustments and other 8,157 4,909 22,983 34,758 Adjusted EBITDA $ 172,083 $ 160,200 $ 781,655 $ 811,204 Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates 3,013 3,229 14,468 10,351 Adjusted EBITDA including unconsolidated affiliates1 $ 175,096 $ 163,429 $ 796,123 $ 821,555

RECONCILIATIONReconciliation of Adjusted EBITDA Margin including unconsolidated affiliates to Operating Profit Margin Adjusted EBITDA including unconsolidated affiliates includes our share in EBITDA of unconsolidated affiliates. (in thousands of U.S. dollars) For the three-month period ended December 31, For the twelve-month period ended December 31, 2020 2019 2020 2019 Revenue $ 244,526 $ 213,289 $ 1,013,260 $ 1,011,452 Profit/(loss) for the period attributable to the Company $ (49,241) $ 1,303 $ 11,968 $ 62,135 Profit/(loss) attributable to non-controlling interest 7,948 4,925 4,906 12,473 Income tax (202) (16,029) 24,877 30,950 Share of loss/(profit) of associates carried under the equity method (2,758) (3,576) (510) (7,457) Financial expense, net 109,899 97,711 331,810 402,348 Operating profit $ 65,646 $ 84,334 $ 373,051 $ 500,449 Operating profit margin 26.8% 39.5% 36.8% 49.5% Depreciation, amortization, and impairment charges 43.5% 35.6% 40.3% 30.7% Adjusted EBITDA margin 70.4% 75.1% 77.1% 80.2% Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates 1.2% 1.5% 1.4% 1.0% Adjusted EBITDA Margin including unconsolidated affiliates1 71.6% 76.6% 78.6% 81.2%

RECONCILIATIONReconciliation of 2021 Target Guidance for Adjusted EBITDA including unconsolidated affiliates to CAFD (in millions of U.S. dollars) Guidance1 2021E Adjusted EBITDA including unconsolidated affiliates 820 – 860 Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates (10) – (15) Dividends from equity method investments 20 – 30 Non-monetary items (20) – (30) Net interest and income tax paid (280) – (300) Principal amortization of indebtedness (290) – (310) Changes in other assets and liabilities and change in available cash at project level 0 – 20 Cash Available For Distribution 220 – 240 The forward-looking measures of 2021 Adjusted EBITDA and CAFD are non-GAAP measures that cannot be reconciled to the most directly comparable GAAP financial measure without unreasonable effort primarily because of the uncertainties involved in estimating forward looking income tax expense, mark-to-market changes in derivatives, profit attributable to non-controlling interest and Share of loss/(profit) of associates carried under the equity method to arrive at net income and which are subtracted therefrom to arrive to CAFD.

Great West House, GW1, 17th floor,Great West RoadBrentford TW8 9DFLondon (United Kingdom)

SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

| Atlantica Sustainable Infrastructure plc
Date: March 1, 2021 | By: | /s/ Santiago Seage
|  | Name: | Santiago Seage
|  | Title: | Chief Executive Officer