Additional Expenses recognized during period.

No definition available.

Name:	birk_AdditionalExpensesRecognizedDuringPeriod
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Marketing expenses.

+ References

No definition available.

+ Details

Name:	birk_MarketingExpenses
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Non-Employee director cash compensation per year.

+ References

No definition available.

+ Details

Name:	birk_NonEmployeeDirectorCashCompensationPerYear
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Related party, lease liabilities.

+ References

No definition available.

+ Details

Name:	birk_RelatedPartyLeaseLiabilities
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Related party transactions income.

+ References

No definition available.

+ Details

Name:	birk_RelatedPartyTransactionsIncome
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Shares repurchased amount of ordinary shares.

+ References

No definition available.

+ Details

Name:	birk_SharesRepurchasedAmountOfOrdinaryShares
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Shares repurchased of ordinary shares

+ References

No definition available.

+ Details

Name:	birk_SharesRepurchasedOfOrdinaryShares
Namespace Prefix:	birk_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

TRA liability.

+ References

No definition available.

+ Details

Name:	birk_TraLiability
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amounts payable resulting from related party transactions. [Refer: Total for all related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2024-01-01
-Paragraph 20
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2024-en-r&anchor=para_20&doctype=Standard
-URIDate 2024-03-27

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-IssueDate 2024-01-01
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-URIDate 2024-03-27

+ Details

Name:	ifrs-full_AmountsPayableRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amounts receivable resulting from related party transactions. [Refer: Total for all related parties [member]]

+ References

+ Details

Name:	ifrs-full_AmountsReceivableRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

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

- Definition

The amount of compensation to key management personnel. [Refer: Key management personnel of entity or parent [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2024-01-01
-Paragraph 17
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2024-en-r&anchor=para_17&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_KeyManagementPersonnelCompensation
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of leases where the entity was the lessee in related party transactions. [Refer: Total for all related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2024-01-01
-Paragraph 21
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2024-en-r&anchor=para_21_d&doctype=Standard
-URIDate 2024-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of revenue arising from the sale of goods in related party transactions. [Refer: Revenue; Total for all related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2024-01-01
-Paragraph 21
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2024-en-r&anchor=para_21_a&doctype=Standard
-URIDate 2024-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of assets that represent a lessee's right to use an underlying asset for the lease term that do not meet the definition of investment property. Underlying asset is an asset that is the subject of a lease, for which the right to use that asset has been provided by a lessor to a lessee.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2024-01-01
-Paragraph 53
-Subparagraph j
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2024-en-r&anchor=para_53_j&doctype=Standard
-URIDate 2024-03-27

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-URIDate 2024-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of services received in related party transactions. [Refer: Total for all related parties [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2024-01-01
-Paragraph 21
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2024-en-r&anchor=para_21_c&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_ServicesReceivedRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ifrs-full_NonadjustingEventsAfterReportingPeriodAxis=birk_OrdinaryShareTransactionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=birk_OckenfelsGroupGmbhAndCoKgMember
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_ClassesOfAssetsAxis=birk_OtherAssetsCurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=birk_OtherFinancialLiabilitiesCurrentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_OtherRelatedPartiesMember
Namespace Prefix:
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Related Party - Additional Information (Details) - EUR (€)			3 Months Ended		9 Months Ended
	May 30, 2025	Oct. 10, 2023	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Sep. 30, 2024
Disclosure of transactions between related parties [line items]
Non-employee director cash compensation per year					€ 300,000	€ 300,000
Right of use Assets			€ 171,943,000		171,943,000		€ 171,334,000
Ordinary Shares
Disclosure of transactions between related parties [line items]
Shares repurchased of ordinary shares	3,927,344	5,648,465
Shares repurchased amount of ordinary shares			176,400,000		176,400,000
Ockenfels
Disclosure of transactions between related parties [line items]
Lease payments			200,000	€ 200,000	400,000	400,000
Lease liability			1,000,000		1,000,000		1,300,000
Right of use Assets			900,000		900,000		1,200,000
Income			0	0	100,000
Restricted Share Units
Disclosure of transactions between related parties [line items]
Expenses recognized during period			100,000	100,000	300,000	200,000
Other Curret Assets \| Ockenfels
Disclosure of transactions between related parties [line items]
Outstanding receivables			9,800,000		9,800,000		9,800,000
Other Financial Liabilities - Current \| Ockenfels
Disclosure of transactions between related parties [line items]
Outstanding payables			1,800,000		1,800,000		1,800,000
Other related parties [member]
Disclosure of transactions between related parties [line items]
Marketing expenses			0	100,000	100,000	100,000
Lease liability			900,000		900,000		200,000
Right of use Assets			900,000		900,000		200,000
Consulting fees and cost reimbursements			100,000	100,000	300,000	400,000
Sales			100,000	200,000	500,000	600,000
TRA liability			364,200,000		364,200,000		€ 359,900,000
Director compensation			€ 200,000	€ 200,000	€ 400,000	€ 400,000