Banking and commitment fees paid.

No definition available.

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Balance Type:	debit
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- Definition

Banking and issuance fees paid.

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

Borrowings maturity extension term.

+ References

No definition available.

+ Details

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- Definition

Commitment fee percentage.

+ References

No definition available.

+ Details

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- Definition

Credit facility balance, current available and remains undrawn amount.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Credit facility, outstanding balance.

+ References

No definition available.

+ Details

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

- Definition

Debt instrument covenant net leverage ratio.

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
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- Definition

Effective date of executing agreement.

+ References

No definition available.

+ Details

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- Definition

Loan capital term period.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Number of times maturity date extended.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Revolving credit ancillary facility.

+ References

No definition available.

+ Details

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

- Definition

Vendor loan

+ References

No definition available.

+ Details

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

- Definition

Voluntary prepayment of debt.

+ References

No definition available.

+ Details

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

- Definition

The amount of outstanding funds that the entity is obligated to repay.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
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Balance Type:	credit
Period Type:	instant

- Definition

The interest rate on borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
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- Definition

The maturity of borrowings. [Refer: Borrowings]

+ References

+ Details

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- Definition

The currency in which the borrowings are denominated. [Refer: Borrowings]

+ References

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of future capital expenditures that the entity is committed to make.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name IAS
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-URIDate 2025-03-27

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of loans received.

+ References

+ Details

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

- Definition

The amount of net debt of the entity.

+ References

+ Details

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

- Definition

The percentage of voting equity interests acquired in a business combination. [Refer: Total for all business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
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-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2025-en-r&anchor=para_B64_c&doctype=Appendix&subtype=B
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Period Type:	instant

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Loans and Borrowings - Additional Information (Details)							12 Months Ended
Loans and Borrowings - Additional Information (Details)	Aug. 02, 2024 EUR (€)	May 28, 2024 EUR (€)	Apr. 30, 2021 EUR (€) Extension	Apr. 29, 2021 EUR (€)	Apr. 28, 2021 EUR (€)	Apr. 28, 2021 USD ($)	Sep. 30, 2025 EUR (€)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 EUR (€)	Sep. 30, 2024 USD ($)	May 28, 2024 USD ($)	Apr. 28, 2021 USD ($)
EUR Term Loan \| USD
Disclosure of detailed information about borrowings [line items]
Voluntary prepayment \| $								$ 50,000,000		$ 100,000,000
Senior Notes
Disclosure of detailed information about borrowings [line items]
Maturity date				April 30, 2029
Interest rate				5.25%
Debt offering				€ 430,000,000
Banking and issuance fees paid				€ 14,300,000
Percentage of equity interests							100.00%
Revolving Credit Facility
Disclosure of detailed information about borrowings [line items]
Maturity date	February 28, 2029
Revolving credit ancillary facility							€ 10,000,000
Credit facility, available and remains undrawn balance							€ 215,000,000
Commitment fee percentage	0.50%
Revolving Credit Facility \| Maximum
Disclosure of detailed information about borrowings [line items]
Credit facility balance	€ 225,000,000
Birkenstock Limited Partner \| EUR Term Loan
Disclosure of detailed information about borrowings [line items]
Banking and commitment fees paid					€ 2,800,000	$ 1,600,000
Birkenstock Limited Partner S A R L
Disclosure of detailed information about borrowings [line items]
Loan of credit facility		€ 375,000,000
Effective Date of Executing Agreement		Aug. 02, 2024
Birkenstock Limited Partner S A R L \| Minimum \| USD
Disclosure of detailed information about borrowings [line items]
Interest rate		1.90%									1.90%
Birkenstock Limited Partner S A R L \| Minimum \| Euro
Disclosure of detailed information about borrowings [line items]
Interest rate		1.60%									1.60%
Birkenstock Limited Partner S A R L \| Maximum \| USD
Disclosure of detailed information about borrowings [line items]
Interest rate		2.60%									2.60%
Birkenstock Limited Partner S A R L \| Maximum \| Euro
Disclosure of detailed information about borrowings [line items]
Interest rate		2.60%									2.60%
Birkenstock Limited Partner S A R L \| New Term Loan
Disclosure of detailed information about borrowings [line items]
Maturity date		February 28, 2029
Birkenstock Limited Partner S A R L \| EUR Term Loan \| USD
Disclosure of detailed information about borrowings [line items]
Loan of credit facility \| $											$ 280,000,000
Senior Term Facilities Agreement \| Birkenstock Limited Partner \| EUR Term Loan
Disclosure of detailed information about borrowings [line items]
Maturity date					April 30, 2028	April 30, 2028
Borrowings original currency							the Euro- and USD-denominated components	the Euro- and USD-denominated components
Senior Term Facilities Agreement \| Birkenstock Limited Partner \| EUR Term Loan \| USD
Disclosure of detailed information about borrowings [line items]
Banking and commitment fees paid					€ 22,700,000
Senior Term Facilities Agreement \| Birkenstock Limited Partner \| EUR Term Loan \| Euro
Disclosure of detailed information about borrowings [line items]
Banking and commitment fees paid					15,400,000
Senior Term Facilities Agreement \| Birkenstock Limited Partner \| EUR Term Loan \| Maximum
Disclosure of detailed information about borrowings [line items]
Borrowings					€ 375,000,000							$ 850,000,000
Asset-based Lending Facility
Disclosure of detailed information about borrowings [line items]
Loan capital term period					5 years	5 years
Commitment fee percentage					0.375%	0.375%
Asset-based Lending Facility \| Maximum
Disclosure of detailed information about borrowings [line items]
Loan capital					€ 200,000,000
Vendor Loan Agreement
Disclosure of detailed information about borrowings [line items]
Voluntary prepayment							€ 0		€ 100,000,000
Vendor Loan Agreement \| AB-Beteiligungs GmbH
Disclosure of detailed information about borrowings [line items]
Vendor loan			€ 275,000,000
Interest rate			4.37%
Vendor Loan Agreement \| AB-Beteiligungs GmbH \| Maximum
Disclosure of detailed information about borrowings [line items]
Number of times maturity date extended \| Extension			3
Maturity extension term			6 months
Vendor Loan Agreement \| AB-Beteiligungs GmbH \| Vendor Loan
Disclosure of detailed information about borrowings [line items]
Maturity date			October 30, 2029
Term and Revolving Facilities Agreement \| Maximum
Disclosure of detailed information about borrowings [line items]
Net leverage ratio	3.5
Term and Revolving Facilities Agreement \| Birkenstock Limited Partner S A R L
Disclosure of detailed information about borrowings [line items]
Effective Date of Executing Agreement	Aug. 02, 2024