The men were located by the Sligo-based Coastguard helicopter after their 36 foot fishing vessel sank yesterday afternoon.
The alarm was raised after they failed to return by nightfall to Porturlin Harbour.
They spent almost 12 hours adrift in a life raft.
They were found 13 miles north west of Downpatrick Head at around 1am.
A coastguard helicopter and the Ballyglass lifeboat were involved in an extensive air and sea search off Downpatrick Head for the missing men.
The Marine Casulty Investigations Board is to carry out an investigation into the sinking of the boat.
