v3.26.1
Cover - shares
 3 Months Ended
Mar. 31, 2026
May 08, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity File Number 001-42921  
Document Period End Date Mar. 31, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Entity Registrant Name Dynamix Corporation III  
Current Fiscal Year End Date --12-31  
Entity Central Index Key 0002081125  
Amendment Flag false  
Entity Incorporation, State or Country Code E9  
Entity Tax Identification Number 00-0000000  
Entity Address, Address Line One 1980 Post Oak Blvd.  
Entity Address, Address Line Two Suite 100PMB 6373  
Entity Address, City or Town Houston  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 77056  
City Area Code (646)  
Local Phone Number 792 5600  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company true  
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 DNMXU  
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 DNMX  
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 DNMXW  
Security Exchange Name NASDAQ  
Class A Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   20,125,000
Class B Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   6,708,333