The three were identified as Paul Bolger, 50, and his brothers, Kenny, 47, and Shane, 45, The Irish Times reported. A search began when they failed to return to Dunmore East in County Waterford.
A coast guard helicopter and a cutter quickly located all three bodies, officials said. All three were wearing life jackets, suggesting they were killed by hypothermia after hours in the frigid water of the Irish Sea.
About 20 people, including family members, waited on the dock for news during the search.
The brothers were using a 20-foot punt to set their traps off Brownstone Head. Other fishermen said they were experienced boat handlers.