v3.26.3
Cover Page
 12 Months Ended
Dec. 31, 2025
shares
Entity Information [Line Items]  
Document Type 20-F/A
Amendment Flag true
Entity Registrant Name COSAN S.A.
Document Fiscal Year Focus 2025
Document Fiscal Period Focus FY
Entity Central Index Key 0001430162
Current Fiscal Year End Date --12-31
Document Period End Date Dec. 31, 2025
Document Registration Statement false
Document Annual Report true
Document Transition Report false
Document Shell Company Report false
Entity File Number 001-40155
Entity Incorporation, State or Country Code D5
Entity Address, Address Line One Av. Brigadeiro Faria Lima, 4,100 – 16th floor
Entity Address, City or Town São Paulo
Entity Address, Postal Zip Code 04538-132
Entity Address, Country BR
Entity Common Stock, Shares Outstanding 3,966,570,932
Entity Well-known Seasoned Issuer Yes
Entity Voluntary Filers No
Entity Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Large Accelerated Filer
Entity Emerging Growth Company false
ICFR Auditor Attestation Flag true
Document Financial Statement Error Correction [Flag] false
Document Accounting Standard International Financial Reporting Standards
Entity Shell Company false
Auditor Name PricewaterhouseCoopers Auditores Independentes Ltda.
Auditor Firm ID 1351
Auditor Location São Paulo, Brazil
Amendment Description We are amending our Annual Report on Form 20-F for the fiscal year ended December 31, 2025 as originally filed with the U.S. Securities and Exchange Commission (the “SEC”) on April 10, 2026 (the “Original Annual Report”) for the purpose of filing with the SEC the financial statements for the fiscal years ended March 31, 2026, 2025 and 2024 of Raízen S.A. as Exhibit 15.2.
Business Contact [Member]  
Entity Information [Line Items]  
Contact Personnel Name José Cezário Menezes de Barros Sobrinho
Entity Address, Address Line One Av. Brigadeiro Faria Lima, 4,100 – 16th floor
Entity Address, City or Town São Paulo
Entity Address, Postal Zip Code 04538-132
Entity Address, Country BR
City Area Code +55 11
Local Phone Number 3897-9797
Common Shares [Member]  
Entity Information [Line Items]  
Title of 12(b) Security Common shares, no par value
ADR [Member]  
Entity Information [Line Items]  
Title of 12(b) Security American depositary shares, each representing four common shares, no par value