Three people were rescued from the water in Lough Derg yesterday afternoon.
Valentia Coast Guard called on Lough Derg RNLI following reports of three people in difficulty on a boat in Portumna.
The RNLI says one person fell overboard attempting to start their boat after an engine failure, and was recovered by two others, who got into the water to help him.
They raised the alarm, saying one of their group needed immediate medical attention.
The operation involved the coast guard, the fire service, gardaí and the RNLI.
One person was suffering from hypothermia, and all three were transferred into the care of the ambulance crew.