The weighted average number of ordinary shares outstanding plus the weighted average number of ordinary shares that would be issued on the conversion of all the dilutive potential ordinary shares into ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 33
-IssueDate 2025-01-01
-Paragraph 70
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=33&code=ifrs-tx-2025-en-r&anchor=para_70_b&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_AdjustedWeightedAverageShares
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The potential dilutive effect on the weighted average number of ordinary shares that relate to the assumed exercise of the entity's share options.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 33
-IssueDate 2025-01-01
-Paragraph 70
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=33&code=ifrs-tx-2025-en-r&anchor=para_70_b&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_DilutiveEffectOfShareOptionsOnNumberOfOrdinaryShares
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_EarningsPerShareLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of ordinary shares outstanding at the beginning of the period, adjusted by the number of ordinary shares bought back or issued during the period multiplied by a time-weighting factor.

+ References

+ Details

Name:	ifrs-full_WeightedAverageShares
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	tsat_EffectOfDilutedSecuritiesAbstract
Namespace Prefix:	tsat_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_TypesOfAntidilutiveInstrumentsAxis=ifrs-full_ShareOptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfAntidilutiveInstrumentsAxis=ifrs-full_RestrictedShareUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfAntidilutiveInstrumentsAxis=tsat_DeferredShareUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfAntidilutiveInstrumentsAxis=ifrs-full_PreferenceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Earnings Per Share - Schedule of Reconciliations of the Denominators of the Basic and Diluted Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Schedule of Reconciliations of the Denominators of the Basic and Diluted Per Share [Line Items]
Basic total weighted average number of Telesat Corporation Shares outstanding	14,797,243	14,046,257	14,592,627	13,888,334
Effect of diluted securities
Diluted total weighted average number of Telesat Corporation Shares outstanding	14,797,243	16,059,104	14,592,627	15,813,555
Stock options [Member]
Effect of diluted securities
Effect of diluted securities		48,137		18,437
RSUs [Member]
Effect of diluted securities
Effect of diluted securities		1,173,594		1,194,740
DSUs [Member]
Effect of diluted securities
Effect of diluted securities		168,020		148,120
PSUs [Member]
Effect of diluted securities
Effect of diluted securities		623,096		563,924