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 May, 2022
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).

Q1 2022 Earnings Presentation May 9, 2022

DISCLAIMER Forward Looking Statements This 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," "could," "estimate," "expect," "forecast," "guidance," "intend," "may," "plan," "predict," "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 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 4.B. Information on the Company—Business Overview", each in our Annual Report on Form 20-F for the fiscal year ended December 31, 2021, filed with the Securities and Exchange Commission (“SEC”), 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, expected investments in expansions; equity investment; estimated returns and cash available for distribution (“CAFD”) estimates, CAFD estimates per currency, geography and sector; net corporate leverage based on CAFD estimates; debt refinancing; 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; 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 on Form 20-F for the fiscal year ended December 31, 2021 filed with the SEC. The CAFD and other guidance included in this presentation are estimates as of May 9, 2022. These estimates are based on assumptions believed to be reasonable as of the date Atlantica Sustainable Infrastructure plc (“Atlantica”, the “Company”, “we” or “us”) published its First Quarter 2022 Financial Results. We disclaim 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, Adjusted EBITDA as a percentage of revenues (margin), CAFD and CAFD per share. 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 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 Revenue and Adjusted EBITDA growth of 7.0%1 and 4.8%1 in Q1 2022, on a comparable basis $140 - 150 million in equity investments already closed or earmarked for 2022 Q1 2022 dividend of $0.44 per share Compared to the three-month period ended March 31, 2021, on a constant currency basis and adjusted for the consolidation of a non-recurrent Rioglass solar project in the three-month period ended March 31, 2022. +6.3% year-over-year CAFD growth in Q1 2022 up to $54.4 million

∆ Excluding FX impact & non-recurrent project US $ in million (except CAFD per share) 2022 2021 ∆ Reported Revenue 247.5 268.2 (7.7)% Adjusted EBITDA1 173.6 171.2 1.4% Margin2 70.2% 63.8% CAFD 54.4 51.2 6.3% CAFD per share4 0.48 0.46 4.0% HIGHLIGHTS 6.3% CAFD Growth in Q1 2022 Adjusted EBITDA previously excluded share of profit/(loss) of associates carried under the equity method and did not include depreciation and amortization, financial expense and income tax expense of unconsolidated affiliates (pro-rata of our equity ownership) (which is equivalent to our pro-rata share of Adjusted EBITDA from unconsolidated affiliates) and now includes it (see reconciliation on page 25). Prior periods have been presented accordingly. Adjusted EBITDA Margin is defined as Adjusted EBITDA divided by revenue (see reconciliation on page 27). Compared to the three-month period ended March 31, 2021, on a constant currency basis and adjusted for the consolidation of a non-recurrent Rioglass solar project in the three-month period ended March 31, 2021. Calculated by dividing CAFD for the period by weighted average number of shares for the period (see reconciliation on page 26). 7.0%3 First Quarter 4.8%3

HIGHLIGHTS Performance by Sector and Region WATER Q1 2022 Q1 2021 ∆ 13.5 13.5 0% 9.2 9.8 (6)% 68% 73% RENEWABLES Q1 2022 Q1 20212 ∆ 182.1 199.7 (9)% 122.2 117.0 +4% 67% 59% EFFICIENT NAT. GAS & HEAT Q1 2022 Q1 2021 ∆ 25.3 28.4 (11)% 21.7 23.2 (6)% 86% 82% TRANSMISSION LINES Q1 2022 Q1 2021 ∆ 26.6 26.6 0% 20.5 21.2 (3)% 77% 80% By Sector US $ in million Revenue Margin EMEA NORTH AMERICA Q1 2022 Q1 2021 ∆ 74.4 60.6 +23% 58.3 40.3 +45% 78% 67% SOUTH AMERICA Q1 2022 Q1 20211 ∆ 134.6 169.3 (20)% 86.2 101.0 (15)% 64% 60% By Region US $ in million Revenue Adjusted EBITDA Margin Q1 2022 Q1 2021 ∆ 38.5 38.3 1% 29.1 29.9 (3)% 76% 78% Adjusted EBITDA Includes Revenue and Adjusted EBITDA of a non-recurrent Rioglass solar project. Compared to the three-month period ended March 31, 2021, on a constant currency basis and excluding the effect from the non-recurrent solar project, Revenue for the three-month period ended March 31, 2022 increased 2.0% and Adjusted EBITDA decreased 9.2%. Includes Revenue and Adjusted EBITDA of a non-recurrent Rioglass solar project. Compared to the three-month period ended March 31, 2021, on a constant currency basis and excluding the effect from the non-recurrent solar project, Revenue and Adjusted EBITDA for the three-month period ended March 31, 2022 increased 11.7% and 9.3%, respectively.

Includes 49% of Vento II production since its acquisition in June 2021. Includes curtailment in wind assets for which we receive compensation. Represents total installed capacity in assets owned or consolidated at the end of the period, regardless of our percentage of ownership in each of the assets, except for Vento II, for which we have included our 49% interest. GWh produced includes 30% share of the production from Monterrey. 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 43 MW corresponding to our 30% share in Monterrey and 55 MWt corresponding to thermal capacity from Calgary District Heating. WATER RENEWABLES TRANSMISSION LINES EFFICIENT NATURAL GAS & HEAT Q1 2022 Q1 2021 Availability4 104.5% 97.5% Mft3 in operation2 17.5 17.5 Q1 2022 Q1 2021 GWh produced1 1,094 606 MW in operation2 2,044 1,591 Q1 2022 Q1 2021 GWh produced3 625 542 Availability4 100.3% 98.3% MW in operation5 398 343 Q1 2022 Q1 2021 Availability4 99.9% 100.0% Miles in operation 1,229 1,166 KEY OPERATIONAL METRICS Steady Operational Performance

Consolidated cash as of March 31, 2022, decreased by $116.3 million vs December 31, 2021, including FX translation differences of $0.7 million. CASH FLOW Operating Cash Flow US $ in million 2022 2021 Adjusted EBITDA 173.6 171.2 Share in Adjusted EBITDA of unconsolidated affiliates (14.2) (3.3) Net interest and income tax paid (16.5) (30.9) Variations in working capital (19.0) 17.1 Non-monetary adjustments and other 13.5 (6.9) OPERATING CASH FLOW 137.3 147.1 Acquisitions of subsidiaries & entities under equity method (39.0) (10.7) Distributions from entities under the equity method & other 26.1 4.3 INVESTING CASH FLOW (12.9) (6.4) FINANCING CASH FLOW (8.8) 66.9 Net change in consolidated cash1 115.6 207.6 First Quarter

1 US $ in million 2022 ~50% of target already closed or committed Including $8 million expected to be invested in an expansion of the Chile TL4 asset and a related substation in 2022 or 2023. Includes investments in the first quarter of 2022 and an estimation for the rest of 2022. GROWTH UPDATE Expected Investments for 2022 2

Appendix

fixed or hedged1 Project Debt (1) As of December 31, 2021. (2) See our Annual Report on form 20-F for the fiscal year ended December 31, 2021 for additional information on the specific interest rates and hedges. (3) Percentage fixed or hedged. INTEREST RATE RISK COVERAGE 94%1 of Debt Fixed or Hedged2 ASSET INTEREST TYPE FIXED1,3 Solana Fixed 100% Mojave Fixed 100% Coso Hedged 100% Chile PV 1&2 Hedged 75% Palmatir Hedged 80% Cadonal Hedged 73% Melowind Hedged 75% Solaben 2 Hedged 100% Solaben 3 Hedged 100% Logrosan5 Hedged 100% Solacor 1 Hedged 99% Solacor 2 Hedged 98% PS 20 Hedged 100% Helioenergy 1 Hedged 100% Helioenergy 2 Hedged 100% Helios 1/2 Hedged 100% Solnova 1 Hedged 100% Solnova 3 Hedged 100% Solnova 4 Hedged 100% Solaben 1/6 Fixed 100% Kaxu Hedged 58% ACT Hedged 75% ATN Fixed 100% ATS Fixed 100% ATN 2 Fixed 100% Quadra 1 & 2 Hedged 75% Skikda Fixed 100% Tenes Fixed 100% Other Hedged 71% Hedged4 54.4% Fixed4 38.7% Total Fixed or Hedged 93.1% (4) Weighted average based on outstanding balance as of December 31, 2021. (5) Subholding company of Solaben 1, 2, 3 & 6. (6) Other facilities include the Commercial Paper Program, accrued interest payable and other debts. (7) 97% as of March 31, 2022 due to the balance drawn down against the Revolving Credit Facility. INSTRUMENT INTEREST TYPE DEC 31, 2021 Revolving Credit Facility Variable - Green Exchangeable Notes Fixed 104 2020 Green Private Placement Fixed 327 Note Issuance Facility 2020 Hedged (100%) 156 Green Senior Notes Fixed 394 Other facilities6 Fixed 41 Total Outstanding Debt 1,023 Hedged4 15.2% Fixed4 84.8% Total Fixed or Hedged 100.0%7 Corporate Debt of Corporate Debt ~100% of Project Debt & ~93%

CURRENCY2 SECTOR GEOGRAPHY Based on CAFD estimates for the 2022-2026 period, including the acquisitions closed as of February 28, 2022. See “Disclaimer – Forward Looking Statements”. Including the effect of currency hedges. As of December 31, 2021. of long-term interest rates in project debt are fixed or hedged2,3 ~ 93% 90 Denominated in USD % > 70% Renewable 15% Eff. Natural Gas & Heat 12% Transmission Lines 3% Water 46% North America 31% Europe 15% South America 8% RoW SIZEABLE AND DIVERSIFIED ASSET PORTFOLIO Portfolio Breakdown Based on Estimated CAFD1 INTEREST RATES AND INFLATION Indexed to inflation or formula based on inflation Indexed to a fixed number Not indexed Escalation factors included in contracts

HISTORICAL FINANCIAL REVIEW Key Financials by Quarter (1/2) “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 to this presentation. Dividends are paid to shareholders in the quarter after they are declared. (3) Number of shares outstanding on the record date corresponding to each dividend, except the shares issued under the ATM program between the dividend declaration date and the dividend record date. 1Q20 2Q20 3Q20 4Q20 2020 1Q21 2Q21 3Q21 4Q21 2021 1Q22 Revenues 210,403 255,344 302,987 244,526 1,013,260 268,178 342,997 329,244 271,331 1,211,749 247,452 Adjusted EBITDA 165,962 214,107 240,958 175,096 796,123 171,249 232,984 229,846 190,307 824,388 173,626 Adj. EBITDA margin (%) 78.9% 83.9% 79.5% 71.6% 78.6% 63.8% 67.9% 69.8% 70.1% 68,0% 70.2% Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates (3,553) (3,959) (3,943) (3,013) (14,468) (3,298) (4,295) (8,451) (15,013) (31,057) (14,202) Dividends from unconsolidated affiliates 5,120 5,262 9,758 2,106 22,246 8,799 4,431 11,385 10,268 34,883 31,870 Non-monetary items (9,823) (9,161) (10,843) (14,116) (43,943) (6,834) 8,622 33,675 20,346 55,809 10,413 Accounting provision for electricity market prices in Spain (5,489) (5,478) (5,516) (5,827) (22,311) (659) 11,643 41,582 24,489 77,055 7,141 Difference between billings and revenue in assets accounted for as concessional financial assets 10,383 11,034 9,390 12,536 43,344 9,167 10,993 6,771 11,959 38,890 18,169 Income from cash grants in the US (14,717) (14,717) (14,717) (14,717) (58,868) (14,678) (14,677) (14,678) (14,678) (58,711) (14,643) Other non-monetary items - - - (6,108) (6,108) (664) 664 - (1,424) (1,424) (254) Net interest and income tax paid (11,436) (119,517) (31,625) (124,661) (287,239) (30,872) (132,856) (45,301) (133,234) (342,263) (16,546) Principal amortization of indebtedness net of new indebtedness at projects (14,898) (75,301) (18,963) (151,260) (260,422) (14,972) (104,999) (40,336) (158,684) (318,991) (24,789) Deposits into/withdrawals from debt service accounts1 32,921 17,605 8,844 27,807 87,177 (26,576) 26,383 (567) 27,994 27,233 13,402 Change in non-restricted cash at project companies1 (50,467) 31,257 (94,192) 34,784 (78,618) (71,162) 47,730 (89,947) 115,588 2,209 (103,116) Dividends paid to non-controlling interests (4,915) (9,246) (6,833) (1,950) (22,944) (4,215) (7,395) (11,717) (4,807) (28,134) (6,221) Changes in other assets and liabilities (61,353) (1,330) (41,207) 106,670 2,779 29,118 (11,948) (20,008) 4,308 1,470 (10,030) Cash Available For Distribution (CAFD) 47,558 49,717 51,953 51,463 200,691 51,237 58,657 58,580 57,073 225,547 54,407 Dividends declared2 41,657 42,673 42,673 46,491 173,494 47,643 47,807 48,493 49,479 193,422 50,202 # of shares3 101,601,662 101,601,662 101,601,662 110,691,722 110,797,738 111,178,846 111,477,263 112,451,438 114,095,845 DPS (in $ per share) 0.41 0.42 0.42 0.42 1.67 0.43 0.43 0.435 0.44 1.735 0.44 Key Financials US $ in thousands

Debt details 1Q20 2Q20 3Q20 4Q20 2020 1Q21 2Q21 3Q21 4Q21 2021 1Q22 Project debt 4,777.2 5,007.6 5,281.2 5,237.6 5,237.6 5,200.2 5,374.2 5,278.9 5,036.2 5,036.2 5,037.0 Project cash (535.3) (510.1) (602.2) (533.3) (533.3) (624.6) (603.1) (685.0) (534.4) (534.4) (625.9) Project net debt 4,241.9 4,497.5 4,679.0 4,704.3 4,704.3 4,575.6 4,771.1 4,593,9 4,501.8 4,501.8 4,411.1 Corporate debt 807.3 837.0 959.7 993.7 993.7 965.3 1,025.1 1,030.1 1,023.1 1,023.1 1,056.1 Corporate cash (154.9) (278.7) (186.7) (335.2) (335.2) (434.2) (83.2) (78.6) (88.3) (88.3) (113.1) Corporate net debt 652.4 558.3 773.0 658.5 658.5 531.1 941.8 951.5 934.8 934.8 943.0 Total net debt 4,894.4 5,055.8 5,452.0 5,362.8 5,362.8 5,106.7 5,713.0 5,545.1 5,436.6 5,436.6 5,354.1 Corporate net debt/CAFD pre corporate interests1 2.4x 2.3x 3.3x 3.0x 3.0x 2.6x2 3.4x 3.5x 3.5x 3.5x 3.3x HISTORICAL FINANCIAL REVIEW Key Financials by Quarter (2/2) US $ in million (1) Ratios presented are the ratios shown on each earnings presentation relating to such period. (2) Net corporate debt as of March 31, 2021, was calculated proforma including the payment of $170m ($130m equity investment paid in April 2021 and additional $40m paid in July 2021 to reduce debt).

HISTORICAL FINANCIAL REVIEW Segment Financials by Quarter 1Q20 2Q20 3Q20 4Q20 2020 1Q21 2Q21 3Q21 4Q21 2021 1Q22 by Geography NORTH AMERICA 59,283 98,648 109,757 63,233 330,921 60,585 118,216 129,860 87,114 395,775 74,304 SOUTH AMERICA 35,654 39,375 36,990 39,441 151,460 38,308 40,043 38,778 37,856 154,985 38,528 EMEA 115,466 117,321 156,240 141,852 530,879 169,285 217,726 160,606 146,361 660,989 134,620 by Business Sector RENEWABLES 150,793 193,881 234,556 173,859 753,089 199,679 271,945 254,132 202,768 928,525 182,101 EFFICIENT NAT. GAS & HEAT 26,403 25,629 28,086 30,912 111,030 28,408 30,097 35,019 30,168 123,692 25,327 TRANSMISSION LINES 26,608 26,787 25,834 26,813 106,042 26,614 26,975 26,840 25,251 105,680 26,620 WATER 6,599 9,047 14,511 12,942 43,099 13,477 13,979 13,253 13,143 53,852 13,404 Total Revenue 210,403 255,344 302,987 244,526 1,013,260 268,178 342,996 329,244 271,331 1,211,749 247,452 1Q20 2Q20 3Q20 4Q20 2020 1Q21 2Q21 3Q21 4Q21 2021 1Q22 by Geography NORTH AMERICA 52,661 89,954 95,879 40,871 279,365 40,287 94,574 108,500 68,442 311,803 58,266 88.8% 91.2% 87.4% 64.6% 84.4% 66.5% 80.0% 83.6% 78.6% 78.8% 78.4% SOUTH AMERICA 28,422 31,380 29,947 30,275 120,023 29,943 30,279 30,404 28,921 119,547 29,129 79.7% 79.7% 81.0% 76.8% 79.2% 78.2% 75.6% 78.4% 76.4% 77.1% 75.6% EMEA 84,879 92,773 115,132 103,950 396,735 101,019 108,133 90,942 92,944 393,038 86,231 73.5% 79.1% 73.7% 73.3% 74.7% 59.7% 49.7% 56.6% 63.5% 59.5% 64.1% by Business Sector RENEWABLES 113,670 161,415 181,788 119,412 576,285 117,036 177,995 169,830 137,722 602,583 122,223 75.4% 83.3% 77.5% 68.7% 76.5% 58.6% 65.5% 66.8% 67.9% 64.9% 67.1% EFFICIENT NAT. GAS & HEAT 24,462 23,303 27,479 25,762 101,006 23,182 24,039 29,166 23,548 99,935 21,699 92.6% 90.9% 97.8% 83.3% 91.0% 81.6% 79.9% 83.3% 78.1% 80.8% 85.7% TRANSMISSION LINES 21,922 22,423 21,702 21,225 87,272 21,203 21,319 21,721 19,392 83,635 20,523 82.4% 83.7% 84.0% 79.2% 82.3% 79.7% 79.0% 80.9% 76.8% 79.1% 77.1% WATER 5,908 6,966 9,989 8,697 31,560 9,828 9,633 9,129 9,645 38,235 9,181 89.5% 77.0% 68.8% 67.2% 73.2% 72.9% 68.9% 68.9% 73.4% 71.0% 68.% Total Adjusted EBITDA 165,962 214,107 240,958 175,096 796,123 171,249 232,986 229,846 190,307 824,388 173,626 78.9% 83.9% 79,5% 71.6% 78.6% 63.8% 67.9% 69.8% 70.1% 68.0% 70.2% Adjusted EBITDA Revenue US $ in thousands

1Q20 2Q20 3Q20 4Q20 2020 1Q21 2Q21 3Q21 4Q21 2021 1Q22 RENEWABLES3 (GWh) 526 957 1,125 636 3,244 606 1,377 1,477 1,195 4,655 1,094 (GWh) 644 624 664 642 2,574 542 501 622 627 2,292 625 (availability %) 102.4% 100.9% 103.8% 101.2% 102.1% 98.3% 100.1% 101.1% 103.0% 100.6% 100.3% TRANSMISSION LINES (availability %) 99.9% 99.9% 100.0% 100.0% 100.0% 100.0% 99.9% 100.0% 100.0% 100.0% 99.9% WATER (availability %) 101.8% 102.2% 101.1% 95.4% 100.1% 97.5% 101.9% 99.8% 91.9% 97.9% 104.5% 1Q20 2Q20 3Q20 4Q20 2020 1Q21 2Q21 3Q21 4Q21 2021 1Q22 RENEWABLES1 (MW) 1,496 1,551 1,551 1,551 1,551 1,591 2,018 2,022 2,044 2,044 2,044 EFFICIENT NAT. GAS & HEAT2 (MW) 343 343 343 343 343 343 398 398 398 398 398 TRANSMISSION LINES (Miles) 1,166 1,166 1,166 1,166 1,166 1,166 1,166 1,166 1,166 1,166 1,229 WATER1 (Mft3/day) 10.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 Capacity in operation (at the end of the period) Production / Availability 4 4 4 Represents total installed capacity in assets owned or consolidated at the end of the period, regardless of our percentage of ownership in each of the assets, except for Vento II, for which we have included our 49% interest. Includes 43 MW corresponding to our 30% share in Monterrey since August 2, 2019, and 55 MWt corresponding to thermal capacity from Calgary District Heating since May 14, 2021. Includes 49% of Vento II production since its acquisition. Includes curtailment in wind assets for which we receive compensation. 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 NAT. GAS & HEAT HISTORICAL FINANCIAL REVIEW Key Performance Indicators

Historical Capacity Factors1 1Q20 2Q20 3Q20 4Q20 2020 1Q21 2Q21 3Q21 4Q21 2021 1Q22 SOLAR US 18.2% 37.5% 35.2% 17.6% 27.1% 18.0% 38.6% 31,0% 17.0% 26.1% 17.2% Chile2 - 27.9% 29.8% 38.2% 32.0% 28.4% 20.9% 20.6% 25.8% 23.9% 25.3% Spain 8.0% 22.1% 28.6% 8.3% 16.8% 9.1% 24.8% 29.6% 10.7% 18.6% 7.3% Italy - - - - - - - 18.6% 8.3% 16.5% 12.7% Kaxu 28.9% 8.6% 26.8% 44.7% 27.3% 38.9% 26.9% 20.2% 48.4% 33.6% 36.9% US - - - - - - - 21.6% 35.4% 28.3% 38.1% Uruguay3 34.6% 40.8% 40.6% 42.8% 39.7% 32.6% 38.3% 38.2% 38.3% 36.9% 34.5% 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 Chile PV 1 since Q2 2020 and Chile PV 2 since Q1 2021. Includes curtailment production in wind assets for which we receive compensation. HISTORICAL FINANCIAL REVIEW Capacity Factors WIND

Exchange rates as of March 31, 2022 (EUR/USD = 1.1159) and December 31, 2021 (EUR/USD = 1.1370). Restricted cash is cash which is restricted generally due to requirements of project finance agreements. US $ in million1 As of Mar. 31 2022 As of Dec. 31 2021 As of Mar. 31 2021 Corporate cash at Atlantica 113.1 88.3 434.2 Existing available revolver capacity 393.5 440.0 440.0 Total Corporate Liquidity 506.6 528.3 874.2 Cash at project companies 625.9 534.4 624.6 - Restricted2 245.7 254.3 310.7 - Other 380.2 280.1 313.9 LIQUIDITY Liquidity Position

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 project subsidiaries is the primary obligor minus cash and cash equivalents held by our project subsidiaries. Net corporate leverage is calculated as corporate net debt divided by midpoint 2022 CAFD guidance before corporate debt service. US $ in million As of Mar. 31, 2022 As of Dec. 31, 2021 Corporate Net Debt2 943.0 934.8 Project Net Debt3 4,411.1 4,501.8 NET DEBT Corporate Leverage Corporate net debt / CAFD pre corporate debt service4 3.3x

LIQUIDITY AND DEBT MATURITIES SUMMARY Healthy Balance Sheet and Strong Liquidity Strong Liquidity and No Significant Corporate Debt Maturities in the Short-term ~$507 million @ 31/03/22 Corporate Liquidity ~4.9 years average maturity2 of current corporate debt Revolving Credit Facility’s maturity extended to December 2024 on May 5, 2022. Total limit is $450.0 million, of which $393.5 million are available as of March 31, 2022 ~$507 million available liquidity, out of which $113.1 million is corporate cash as of Mar. 31, 2022 Corporate Debt Maturities1 Corporate Debt is the indebtedness where Atlantica Sustainable Infrastructure plc. is the primary obligor. Corporate Debt Maturities as of March 31, 2022, except for the Revolving Credit Facility’s, for which December 2024 is considered, according to the extension dated May 5, 2022. Corporate Liquidity means cash and cash equivalents held at Atlantica Sustainable Infrastructure plc as of March 31, 2022 plus available capacity under the Revolving Credit Facility as of March 31, 2022. Corporate Cash corresponds to cash and cash equivalents held at Atlantica Sustainable Infrastructure plc. 37 3 4

Key principle: non-recourse project financing in ring-fenced subsidiaries 100% project debt self-amortizing progressively before the end of the contracted life Low interest rate risk, with +93% of interest rates fixed or hedged ~$2bn planned debt reduction in the next 5 years FINANCING Self-Amortizing Project Debt Structure1 Project debt amortization schedule as of December 31, 2021. Ojo actualizar fixed or hedged si cambia Kaxu

Weighted Average Life Project debt term PPAs with predefined prices for ~15 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 FLOW Portfolio of Assets Represents weighted average years remaining as of March 31, 2022. Regulation term in the case of Spain and Chile TL3. (3) From the total amount of $211 million project debt, $74 million are progressively repaid following a theoretical 2036 maturity, with a legal maturity in 2027. The remaining $137 million are expected to be refinanced in or before 2027.

CORPORATE DEBT DETAILS Corporate Debt as of March 31, 2022 No significant maturities in the short term Exchange rates as of March 31, 2022 (EUR/USD = 1.1159 ). Amounts include principal amounts outstanding, unless stated otherwise. As of March 31, 2022, letters of credit with face value in an amount equal to $21.5 million were outstanding and $393.5 million were available under the Revolving Credit Facility. The latter has a total limit of $450 million. The maturity of loans outstanding from time to time under the Revolving Credit Facility was extended from December 2023 to December 2024 pursuant to the Seventh Amendment to the Revolving Credit Facility, dated May 5, 2022. US $ in million1 Maturity Amounts2 Credit Facilities (Revolving Credit Facility)3 20244 34.2 (Other facilities)5 2022 – 2026 48.4 Green Exchangeable Notes6 2025 104.9 2020 Green Private Placement7 (€ denominated) 2026 321.1 Note Issuance Facility 20208 (€ denominated) 2027 153.1 Green Senior Notes9 2028 394.4 Total 1,056.1 (5) Other facilities include the Commercial Paper Program, accrued interest payable and other debts. (4) Senior unsecured notes dated July 17, 2020, exchangeable into ordinary shares of Atlantica, cash, or a combination of both, at Atlantica’s election. Senior secured notes dated April 1, 2020, of €290 million. Refers to the senior unsecured note facility dated July 8, 2020, of €140 million. Green Senior Unsecured Notes dated May 18, 2021, of $400 million.

NON-GAAP FINANCIAL INFORMATION Reconciliation of Non-GAAP Measures Our management believes Adjusted EBITDA, CAFD and CAFD per share 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 and CAFD per share are 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, CAFD and CAFD per share are widely used by other companies in the same industry. Our management uses Adjusted EBITDA, CAFD and CAFD per share as measures of operating performance to assist in comparing performance from period to period and aims to use them on a consistent basis moving forward. 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, CAFD and CAFD per share 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; and the fact that other companies in our industry may calculate Adjusted EBITDA, CAFD and CAFD per share differently than we do, which limits their usefulness as comparative measures. We define Adjusted EBITDA as profit/(loss) for the period attributable to the parent company, after previously adding back loss/(profit) attributable to non-controlling interest, income tax expense, financial expense (net), depreciation, amortization and impairment charges of entities included in our consolidated financial statements and depreciation and amortization, financial expense and income tax expense of unconsolidated affiliates (pro-rata of our equity ownership). Until September 30, 2021, Adjusted EBITDA excluded equity of profit/(loss) of associates carried under the equity method and did not include depreciation and amortization, financial expense and income tax expense of unconsolidated affiliates (pro-rata of our equity ownership). Prior periods have been presented accordingly. CAFD is calculated as cash distributions received by the Company from its subsidiaries minus cash expenses of the Company, including third party debt service and general and administrative expenses. CAFD per share is calculated by dividing CAFD for the period by weighted average number of shares for the period.

NON-GAAP FINANCIAL INFORMATION Reconciliation of Non-GAAP Measures Information presented as the pro-rata share of our unconsolidated affiliates reflects our proportionate ownership of each asset in our property portfolio that we do not consolidate and has been calculated by multiplying our unconsolidated affiliates’ financial statement line items by our percentage ownership thereto. Note 7 to our consolidated financial statements as of and for the period ended March 31, 2022 includes a description of our unconsolidated affiliates and our pro rata share thereof. We do not control the unconsolidated affiliates. Multiplying our unconsolidated affiliates’ financial statement line items by our percentage ownership may not accurately represent the legal and economic implications of holding a noncontrolling interest in an unconsolidated affiliate. We include pro-rata share of depreciation and amortization, financial expense and income tax expense of unconsolidated affiliates because we believe it assists investors in estimating the effect of such items in the profit/(loss) of associates carried under the equity method (which is included in the calculation of our Adjusted EBITDA) based on our economic interest in such unconsolidated affiliates. Each unconsolidated affiliate may report a specific line item in its financial statements in a different manner. In addition, other companies in our industry may calculate their proportionate interest in unconsolidated affiliates differently than we do, limiting the usefulness of such information as a comparative measure. Because of these limitations, the information presented as the pro-rata share of our unconsolidated affiliates should not be considered in isolation or as a substitute for our or such unconsolidated affiliates’ financial statements as reported under applicable accounting principles.

Reconciliation of Cash Available For Distribution and Adjusted EBITDA to Profit for the period attributable to the Company “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. (in thousands of U.S. dollars) For the three-month period ended March 31 2022 2021 Profit/(loss) for the period attributable to the Company (12,042) (19,172) Profit/(loss) attributable to non-controlling interest 2,200 8,108 Income tax (3,906) 15,241 Depreciation and amortization, financial expense and income tax expense of unconsolidated affiliates (pro rata of our equity ownership) 5,982 2,339 Financial expense, net 80,467 81,192 Depreciation, amortization, and impairment charges 100,925 83,541 Adjusted EBITDA 173,626 171,249 Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates (14,202) (3,298) Non-monetary items 10,413 (6,834) Accounting provision for electricity market prices in Spain 7,141 (659) Difference between billings and revenue in assets accounted for as concessional financial assets 18,169 9,167 Income from cash grants in the US (14,643) (14,678) Other non-monetary items (254) (664) Dividends from equity method investments 31,870 8,799 Interest and income tax paid (16,546) (30,872) Principal amortization of indebtedness (24,789) (14,972) Deposits into/ withdrawals from restricted accounts1 13,402 (26,576) Change in non-restricted cash at project level1 (103,116) (71,162) Dividends paid to non-controlling interests (6,221) (4,215) Changes in other assets and liabilities (10,030) 29,118 Cash Available For Distribution 54,407 51,237

RECONCILIATION Reconciliation of Adjusted EBITDA to Net Cash Provided by Operating Activities (in thousands of U.S. dollars) For the three-month period ended March 31 2022 2021 Net cash provided by operating activities 137,315 147,155 Net interest and income tax paid 16,546 30,872 Changes in working capital 19,047 (17,099) Other non-monetary items (10,413) 6,834 Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates and other 11,131 3,487 Adjusted EBITDA 173,626 171,249 Reconciliation of CAFD to CAFD per share For the three-month period ended March 31 2022 2021 CAFD (in thousands of U.S. dollars) 54,407 51,237 Weighted average number of shares (basic) for the period (in thousands) 112,741 110,386 CAFD per share (in U.S. dollars) 0.4826 0.4642

RECONCILIATION Reconciliation of Adjusted EBITDA Margin to Operating Profit Margin Adjusted EBITDA Margin is defined as Adjusted EBITDA divided by revenue (in thousands of U.S. dollars) For the three-month period ended March 31 2022 2021 Revenue 247,452 268,178 Profit/(loss) for the period attributable to the Company (12,042) (19,172) Profit/(loss) attributable to non-controlling interest 2,200 8,108 Income tax (3,906) 15,241 Share of loss/(profit) of associates carried under the equity method (8,221) (960) Financial expense, net 80,467 81,192 Operating profit 58,498 84,409 Operating profit margin 23.6% 31.5% Depreciation, amortization, and impairment charges 40.8% 31.2% Atlantica’s pro-rata share of EBITDA from unconsolidated affiliates 5.7% 1.2% Adjusted EBITDA margin1 70.2% 63.9%

As of March 31, 2022 ASSET TYPE STAKE LOCATION GROSSCAPACITY OFFTAKER RATING1 YEARS INCONTRACT LEFT CURRENCY RENEWABLE ENERGY Solana 100% USA (Arizona) 280 MW APS BBB+/A3/BBB+ 22 USD Mojave 100% USA (California) 280 MW PG&E BB-/--/BB 18 USD Coso 100% USA (California) 135 MW SCPPA & two CCAs5 Investment grade5 17 USD Elkhorn Valley 49% USA (Oregon) 101 MW Idaho Power Company BBB/A3/-- 6 USD Prairie Star 49% USA (Minnesota) 101 MW Great River Energy --/A3/A- 6 USD Twin Groves II 49% USA (Illinois) 198 MW Exelon Generation Co. BBB-/Baa2/-- 4 USD Lone Star II 49% USA (Texas) 196 MW EDPR Not rated 1 USD Chile PV 1 35% Chile 55 MW n/a n/a n/a USD 4 Chile PV 2 35% Chile 40 MW n/a Not rated 9 USD 4 La Sierpe 100% Colombia 20 MW Synermin6 Not rated 14 COP Palmatir 100% Uruguay 50 MW UTE BBB/Baa2/BBB-2 12 USD Cadonal 100% Uruguay 50 MW UTE BBB/Baa2/BBB-2 13 USD Melowind 100% Uruguay 50 MW UTE BBB/Baa2/BBB-2 14 USD Mini-Hydro 100% Peru 4 MW Peru BBB/Baa1/BBB 11 USD 4 Solaben 2/3 70% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 15/16 EUR 3 Solacor 1/2 87% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 15/15 EUR 3 PS 10/20 100% Spain 31 MW Kingdom of Spain A/Baa1/A- 10/12 EUR 3 Helioenergy 1/2 100% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 15/15 EUR 3 Helios 1/2 100% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 15/15 EUR 3 Solnova 1/3/4 100% Spain 3x50 MW Kingdom of Spain A/Baa1/A- 13/13/13 EUR 3 Solaben 1/6 100% Spain 2x50 MW Kingdom of Spain A/Baa1/A- 16/16 EUR 3 Seville PV 80% Spain 1 MW Kingdom of Spain A/Baa1/A- 14 EUR 3 Italy PV 1 100% Italy 1.6 MW Italy BBB/Baa3/BBB 9 EUR 3 Italy PV 2 100% Italy 2.1 MW Italy BBB/Baa3/BBB 9 EUR 3 Italy PV 3 100% Italy 2.5 MW Italy BBB/Baa3/BBB 10 EUR 3 Kaxu 51% South Africa 100 MW Eskom BB-/Ba2/BB-2 13 ZAR Reflects the counterparties’ issuer credit ratings issued by S&P, Moody’s and Fitch, respectively, as of May 9, 2022. 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 GLANCE Sizeable and Diversified Asset Portfolio (5) Refers to the credit rating of two Community Choice Aggregators: Silicon Valley Clean Energy and Monterrey Bar Community Power, both with A rating from S&P; Southern California Public Power Authority, the third off-taker, is not rated. (6) Largest electricity wholesaler in Colombia.

As of March 31, 2022 ASSET TYPE STAKE LOCATION GROSSCAPACITY OFFTAKER RATING1 YEARS INCONTRACT LEFT CURRENCY EFFICIENT NAT. GAS & HEAT Calgary 100% Canada 55 MWt 22 High quality clients3 ~41% A+ or higher3 19 CAD ACT 100% Mexico 300 MW Pemex BBB/Ba3/BB- 11 USD 2 Monterrey 30% Mexico 142 MW Industrial Customers Not rated 16 USD 2 TRANSMISSION LINES ATN 100% Peru 379 miles Peru BBB/Baa1/BBB 19 USD 2 ATS 100% Peru 569 miles Peru BBB/Baa1/BBB 22 USD 2 ATN 2 100% Peru 81 miles Minera Las Bambas Not rated 11 USD 2 Quadra 1/2 100% Chile 49 miles / 32 miles Sierra Gorda Not rated 13/13 USD 2 Palmucho 100% Chile 6 miles Enel Generacion Chile BBB/-/A- 16 USD 2 Chile TL3 100% Chile 50 miles CNE A/A1/A- Regulated USD 2 Chile TL4 100% Chile 63 miles Several Mini-hydro plants Not rated 50 USD WATER Skikda 34% Algeria 3.5 Mft3/day Sonatrach & ADE Not rated 12 USD 2 Honaine 26% Algeria 7 Mft3/day Sonatrach & ADE Not rated 15 USD 2 Tenes 51% Algeria 7 Mft3/day Sonatrach & ADE Not rated 18 USD 2 Reflects the counterparties’ issuer credit ratings issued by S&P, Moody’s and Fitch, respectively, as of May 9, 2022. USD denominated but payable in local currency. Diversified mix of 22 high credit quality clients (~41% A+ rating or higher, the rest unrated). AT A GLANCE Sizeable and Diversified Asset Portfolio

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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: May 5 ,2022 | By: | /s/ Santiago Seage
|  | Name: | Santiago Seage
|  | Title: | Chief Executive Officer