If you cannot swim, do not swim, especially when it comes to the open sea.

That is the advice of experts in the wake of a drowning at Changi.

Last Sunday, a 20-year-old Chinese national drowned in the sea off Changi Beach. He was with three colleagues and in chest-deep water just off the shore when he went under. He could not swim.

The drowning was the latest in a spate of three incidents.

On May 19, a 35-year-old man drowned while fishing in Jurong Lake. He was apparently fishing illegally on the banks. He drowned when he tried to swim across a 20m stretch of water to escape a police patrol.

On May 22 , a canoe instructor, also 35, is believed to have drowned while coaching students at MacRitchie Reservoir. It is not known how he fell into the water.

Experts said that Singapore's beaches are relatively safe, except for non-swimmers. The currents are not very strong.

Associate Professor Wong Poh Poh from the department of geography at the National University of Singapore said: 'East Coast, Pasir Ris, Changi, Sentosa are all safe except for non-swimmers. For a non-swimmer, even safe and shallow water would be dangerous.'

Added Mr Justin Lee, who runs Water Cross, a water sports business at Pasir Ris Beach: 'We swim to our boats at sea sometimes, and it's as calm as a swimming pool. There's usually no fast-flowing current, even at East Coast Park. The most dangerous areas are those in open water, beyond the bay areas.'

Veteran lifeguard and MP Teo Ho Pin said that Singapore's beaches do not drop as steeply as other beaches, such as in Malaysia where the drop can be as deep as 2m.

Read the full story in The Sunday Times today.