At 9.23am, Valentia Coast Guard requested the local lifeboat station to assist the vessel one mile south of Lemon Rock, near Skellig Michael.
Weather conditions at the time were described as fresh, with a north-westerly Force 5 wind.
Arriving on scene, the lifeboat crew were informed the fishing vessel was unable to return to harbour due to mechanical failure.
The volunteers checked that the three crew onboard the fishing boat were safe and well before setting up a tow to bring the fishing vessel safely back into Portmagee Harbour.
Speaking following the callout, Valentia RNLI lifeboat crew member Con O’Shea said: “The fishermen did the right thing calling for assistance. We urge anyone taking to the sea to always wear a lifejacket and carry a means of calling for help.”