Patrick Oliver and his 18-year-old son, Morgan, found the pair near one of the Aran Islands, approximately 20 miles from where they were last seen.
Cousins Ellen Glynn, 17, and Sara Feeney, 23 had gone boarding off Furbo Beach, near the town of Galway, around 9pm on Wednesday evening,
After a strong northeast wind blew them into the sea and a family member was looking missing from them, lifeboat services were called, according to Mike Swan, rescue operations manager at Galway RNLI.
Swan told CNN that the crew on his lifeboat had to be changed three times overnight as they continued their search.
They were assisted in the search and rescue operation by other lifeboats from the suburbs and by three Coast Guard rescue helicopters, the lifeboat service said in a statement.
Oliver joined the checkpoint Thursday morning, eventually finding paddleboarders roughly two miles west of Inis Oisrr, the statement added.
The women were caught in lobster dishes for four or five hours at that stage, Swan said.
Speaking after she was rescued, Glynn told national broadcaster RT: “We were pretty sure we would be found. The only thing I worried about was just how cold we were – we were shaking like leaves.”
The cousins were taken to hospital after their trial. Feeney was laid off Thursday night and Glynn is likely to be able to go home Saturday morning, RT reported.
Describing the moment his team heard the duo had been rescued, Swan told CNN: “We were in cloud nine. It’s the best feeling ever because the whole station was involved.”
He added that Patrick Oliver, who found the drivers’ lanes and his three brothers were all volunteers for RNLI.
“It is in their blood.” he said.
Taoiseach Micheál Martin was among those who praised the rescue services for their work.
“Great news in Galway today highlighting the extraordinary rescue and volunteer service work. The great community spirit shown by all,” he tweeted.