A diver who got into difficulty while swimming near Union Hall in west Cork was to be airlifted to hospital by the Coast Guard helicopter this evening.
A spokesman for the Coast Guard service at Valencia said the man who is in his 30 appeared to be suffering from 'the bends'.
The bends is a decompression sickness which affects divers when they resurface too rapidly.
The man will be treated in a recompression chamber at Cork University Hospital.