v3.26.1
Cover - USD ($)
 12 Months Ended
Dec. 31, 2025
Mar. 27, 2026
Jun. 30, 2025
Document Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Transition Report false    
Document Financial Statement Error Correction [Flag] false    
Entity Interactive Data Current Yes    
ICFR Auditor Attestation Flag false    
Amendment Flag false    
Document Period End Date Dec. 31, 2025    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Entity Registrant Name SIM Acquisition Corp. I    
Entity Central Index Key 0002014982    
Entity File Number 001-42164    
Entity Tax Identification Number 35-2838851    
Entity Incorporation, State or Country Code E9    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Shell Company true    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
Entity Public Float     $ 239,660,000
Entity Address, Address Line One 725 Fifth Avenue    
Entity Address, Address Line Two 22nd Floor    
Entity Address, City or Town New York    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 10022    
City Area Code (833)    
Local Phone Number 746-2001    
Units, each consisting of one Class A Ordinary Share and one-half of one Redeemable Warrant      
Document Information [Line Items]      
Title of 12(b) Security Units, each consisting of one Class A Ordinary Share and one-half of one Redeemable Warrant    
Trading Symbol SIMAU    
Security Exchange Name NASDAQ    
Class A Ordinary Shares, par value $0.0001 per share      
Document Information [Line Items]      
Title of 12(b) Security Class A Ordinary Shares, par value $0.0001 per share    
Trading Symbol SIMA    
Security Exchange Name NASDAQ    
Redeemable Warrants, each whole warrant exercisable for one Class A Ordinary Share at an exercise price of $11.50 per share      
Document Information [Line Items]      
Title of 12(b) Security Redeemable Warrants, each whole warrant exercisable for one Class A Ordinary Share at an exercise price of $11.50 per share    
Trading Symbol SIMAW    
Security Exchange Name NASDAQ    
Class A Ordinary Shares      
Document Information [Line Items]      
Entity Common Stock, Shares Outstanding   23,000,000  
Class B Ordinary Shares      
Document Information [Line Items]      
Entity Common Stock, Shares Outstanding   7,666,667