The volunteer crew of the Mumbles lifeboat were called to assist with a vehicle which accidentally left the road at Limeslade Bay.
Just before 6 am the alarm was raised following a call to UK Coastguard at Milford Haven.
The driver managed to escape and swim to shore.
Both lifeboats launched and were on the scene within 15 minutes.
With no further casualties to search for both boats returned to station and were ready for service .
The driver was taken to hospital by ambulance.