Galwegians lost their grip on a 7-5 half-time lead as Dolphin powered to their third league win at Glenina.
The Cork men showed a clinical edge as scrum half Gary O'Keeffe (2), full-back Jeff Power (2) and prop Christy Condon helped themselves to tries.
'Wegians winger John Cleary darted over for a second-minute try, but Power replied for Dolphin in the 24th minute.
Then three tries in the space of ten minutes moved Dolphin into a 17-7 lead and they were not to be denied.
Galwegians: Tries: John Cleary, Cormac O'Beirne; Cons: Robert
O'Beirne 2
Dolphin: Tries: Jeff Power 2, Gary O'Keeffe 2, Christy Condon; Cons: Barry Keeshan 2
