A major air-sea rescue operation was launched after reports of two individuals in difficulty in the sea off Men’s Beach, Ballybunion, in north Kerry on Thursday afternoon.
Initial reports indicated that one person had died in the incident.
A second casualty is reported to have been recovered from the water and was being worked on by paramedics while being transferred to hospital.
However, it is now understood that the man and woman in their 50s have both died.
Unconfirmed reports indicated that the two individuals are a man and a woman and are part of the same family group.
Locals say it was a sunny day in Ballybunion but a strong breeze made the water choppy and hazardous.
The emergency response included units of the Irish Coast Guard, Gardaí, RNLI, Civil Defence and both the Shannon-based Rescue 115 helicopter and the north Cork-based air ambulance.
The Ballybunion unit of the Irish Coast Guard, Ballybunion Rescue and the RNLI lifeboat based at Cappagh near Kilrush in Co Clare have been tasked to the scene.
The alarm was raised at around 6.30pm.
It is understood that the initial report to emergency services indicated that two people had gotten into difficulty while swimming off Ballybunion beach.
Search and rescue crews were quickly dispatched to the area.
While en route to the scene on the other side of the Shannon Estuary, the Kilrush lifeboat was stood down after it was reported that two people had been recovered.
One is understood to be in a critical condition.
Soon afterwards, the lifeboat was requested to turn around and continue to Ballybunion after the Irish Coast Guard received further information suggesting that a third person could be missing.
The volunteer lifeboat crew immediately proceeded to the search area off Ballybunion.
The Shannon-based Irish Coast Guard helicopter had been on a mission from the Aran Islands to University Hospital Galway when the crew was tasked to the search operation.
Rescue 115 flew directly to Shannon Airport where fire crews were standing by so they could undertake a hot-refuel.
A hot-refuel is when an aircraft is refuelled while the engines are still running.
After the helicopter had been refuelled, the crew made their way directly to the scene to assist in the search.
As the operation continued further information became available to rescue services that suggested there were only two casualties and not a third as feared.
The Kilrush RNLI life about the Rescue 115 were requested to continue to the area and carry out searches as a precaution.
The search and rescue operation was mounted and coordinated by watch officers at the Irish Coast Guard’s marine rescue sub centre on Valentia Island in Kerry.
"Everybody in the community is shocked by what happened and I offer my condolences to the family," Sinn Féin councillor Robert Beasley said.