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v3.26.1

Cover Page | 12 Months Ended
--- | ---
Dec. 31, 2025
Cover [Abstract] |
Document Type | 6-K
Entity File Number | 001-12518
Entity Registrant Name | Banco Santander, S.A.
Entity Address, Address Line One | 28660 Boadilla del Monte (Madrid)
Entity Address, Country | ES
Entity Central Index Key | 0000891478
Amendment Flag | false
Current Fiscal Year End Date | --12-31
Document Period End Date | Dec. 31, 2025
Document Fiscal Year Focus | 2025
Document Fiscal Period Focus | FY

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