v3.25.2
Cover
 12 Months Ended
Mar. 31, 2025
shares
Document Information [Line Items]  
Document Type 20-F
Document Registration Statement false
Document Annual Report true
Document Transition Report false
Document Shell Company Report false
Entity File Number 001-42438
Registrant Name COINCHECK GROUP N.V.
Entity Address, Address Line One Nieuwezijds Voorburgwal
Entity Address, Address Line Two 162
Entity Address, Postal Zip Code 1012 SJ
Entity Address, City or Town Amsterdam
Contact Personnel Email Address coincheckIR@icrinc.com
Entity Common Stock, Shares Outstanding 130,814,526
Entity Well-known Seasoned Issuer No
Entity Voluntary Filers No
Entity Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Non-accelerated Filer
Entity Emerging Growth Company false
Document Financial Statement Error Correction [Flag] false
ICFR Auditor Attestation Flag false
Entity Shell Company false
Amendment Flag false
Central Index Key 0001913847
Current Fiscal Year End Date --03-31
Document Period End Date Mar. 31, 2025
Document Fiscal Year Focus 2025
Document Fiscal Period Focus FY
Document Accounting Standard International Financial Reporting Standards
Entity Incorporation, State or Country Code P7
Entity Address, Country NL
Ordinary shares  
Document Information [Line Items]  
Title of 12(b) Security Ordinary Shares, nominal value €0.01 per share
Trading Symbol CNCK
Security Exchange Name NASDAQ
Exercisable Warrants  
Document Information [Line Items]  
Title of 12(b) Security Warrants, each exercisable to purchase one ordinary share at an exercise price of $11.50 per share
Trading Symbol CNCKW
Security Exchange Name NASDAQ
Business Contact  
Document Information [Line Items]  
Entity Address, Address Line One Nieuwezijds Voorburgwal
Entity Address, Address Line Two 162
Entity Address, Postal Zip Code 1012 SJ
Entity Address, City or Town Amsterdam
Contact Personnel Name Jason Sandberg
Country Region +31
City Area Code 20
Local Phone Number 522-2555
Entity Address, Country NL