A 61 year-old man was airlifted to hospital with a suspected broken ankle after he fell on rocks near Rhoose Point.
The RNLI at Barry Dock sent out its inshore lifeboat to Dams Bay at around 5.15pm on Sunday evening.
The lifeboat, with three crew on board, tackled "lumpy, choppy seas" before arriving at the scene.

They found rescue by sea was not an option due to the injured man's injury, his pain and the rocky location.
The Coastguard helicopter from St Athan was called out to winch the man to safety, before he was taken to hospital for treatment.
Both the inshore lifeboat and the mobile coastguard team from Barry provided support.
Chris White, helm of the Barry Dock inshore lifeboat, said: "No matter how prepared you are, we know accidents can happen. Thankfully, the casualty had a fully charged mobile phone and was able to call the Coastguard for help."
"The coordinated multi-agency response between the Coastguard rescue team, the helicopter crew, and our volunteer lifeboat crew meant we could reach the casualty quickly and safely, despite the conditions."

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