The lifeboat, under the command of coxswain Nick Keogh, was alongside the yacht 20 minutes after launching.
Crew member Ciaran Doyle was put on board the boat to assist with establishing a tow line. He remained onboard the yacht as it was towed into Wicklow Harbour.
The boat with the three people was secured safely alongside the east pier at 9.20am.
Weather conditions in the area at the time were described as wind south west force two, and the sea state was calm.
Speaking after the incident, Keogh said: "We located the 14-metre yacht drifting five miles south east of Wicklow Head. The yacht had lost engine power and with the light winds they were unable to make any headway."
The crew on the call out were coxswain Nick Keogh, mechanic Brendan Copeland, Ciaran Doyle, Dave O'Leary, Carol Flahive, Tommy Murphy, Alan Goucher and Peter McCann.