v3.25.2
Cover - shares
 9 Months Ended
Jun. 30, 2025
Aug. 15, 2025
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Jun. 30, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Entity Information [Line Items]    
Entity Registrant Name Eureka Acquisition Corp  
Entity Central Index Key 0002000410  
Entity File Number 001-42152  
Entity Tax Identification Number 00-0000000  
Entity Incorporation, State or Country Code E9  
Current Fiscal Year End Date --09-30  
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 Contact Personnel [Line Items]    
Entity Address, Address Line One 14 Prudential Tower  
Entity Address, City or Town Singapore  
Entity Address, Country SG  
Entity Address, Postal Zip Code 049712  
Entity Phone Fax Numbers [Line Items]    
City Area Code (+1)  
Local Phone Number 949 899 1827  
Units, consisting of one Ordinary Share, $0.0001 par value, and one Right to acquire one-fifth of one Ordinary Share    
Entity Listings [Line Items]    
Title of 12(b) Security Units, consisting of one Ordinary Share, $0.0001 par value, and one Right to acquire one-fifth of one Ordinary Share  
Trading Symbol EURKU  
Security Exchange Name NASDAQ  
Class A ordinary shares, par value $0.0001 per share    
Entity Listings [Line Items]    
Title of 12(b) Security Class A ordinary shares, par value $0.0001 per share  
Trading Symbol EURK  
Security Exchange Name NASDAQ  
Rights, each whole right to acquire one-fifth of one Class A ordinary share    
Entity Listings [Line Items]    
Title of 12(b) Security Rights, each whole right to acquire one-fifth of one Class A ordinary share  
Trading Symbol EURKR  
Security Exchange Name NASDAQ  
Class A Ordinary Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   3,388,233
Class B Ordinary Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   1,437,500