At midnight Lough Derg RNLI lifeboat Jean Spier launched with helm Eleanor Hooker, Doireann Kennedy, Keith Brennan and Owen Cavanagh on board.
Given the serious nature of the callout, the Irish Coast Guard Search and Rescue Helicopter team, Rescue 115, was tasked from their base at Shannon Airport.
Galway based Gardaí also responded to the emergency and were at Portumna Harbour, having been informed that this was the intended destination for the missing people.
The wind was southerly Force 2/3 It was night but with a full moon and a starlit sky.
As the lifeboat was launching, Valentia Coast Guard requested it go directly to Portumna Castle Harbour at the very northern end of the lake, that the Gardaí had been told that there may be speedboat adrift west of the bay.
Using on-board electronic navigation, RADAR, searchlights and local knowledge the lifeboat made way directly to Portumna Castle Harbour.
At 12.26am as the lifeboat approached Terryglass Bay, Valentia Coast Guard gave the RNLI volunteers a specific location to search.
Very quickly the lifeboat volunteers located three people and a dog on board a 12ft speedboat.
All three people and their dog were safe and unharmed.
They said that having become disorientated and lost, they found themselves in the reeds out of sight of the harbour and out of fuel.
To ensure the lifeboat was attending the same people reported missing, Valentia Coast Guard requested the lifeboat let them know the name of the skipper at the scene.
The lifeboat took the speedboat on an alongside tow to Portumna Castle Harbour, where the casualties were met by Gardaí who checked that they were not in need of further assistance.
Rescue 115 was stood down earlier by Valentia Coast Guard.
At 00.50am the lifeboat departed the scene and was back at Station at 01.12am. At 01.29am the lifeboat was washed down and refuelled.
Peter Kennedy, Deputy Launching Authority at Lough Derg RNLI, advises boat users ‘to plan your passage so that you reach safe harbour before nightfall.
Carry a means of communication and let others know when you expect to arrive at your destination. Carry sufficient lifejackets and ensure all on board are wearing theirs.’