The vessel with three people aboard, which had run aground, was quickly located within 12 minutes of launch.
Weather conditions were good at the time on a clear dry night. There was a low tide and Howth RNLI's XP RIB was prepared and launched from the all-weather lifeboat, manned by volunteer crew members David Howard and Ian Sheridan.
The five-metre motorboat was stuck on a sandbank on the falling tide and was taking on water. The water was pumped from the motorboat, which was then refloated.
Its three passengers were taken safely aboard the all-weather lifeboat and brought back to Howth Marina along with their vessel.
Speaking following the callout, Howth RNLI coxswain Fred Connolly said: "We were pleased to have been able to respond and launch so quickly, locate and recover the casualty vessel.
"There was a very low tide this evening, which contributed to the motorboat running aground, but we compliment the three crew members who immediately called for help as soon as they got into difficulty.
"We also thank our colleagues in the Irish Coast Guard who assisted the rescue from the shore.”