A FIVE-YEAR-OLD boy drowned in a private condominium pool while he was playing with his elder brother and another boy.

See Bing Hong, who could not swim, was taken to Rio Visa condominium at Upper Serangoon View by his mother on Dec 31 last year.

He was using a float to swim in the 1.2m-deep adult pool together with his six-year-old brother and a five-year-old boy.

Bing Hong's mother was in the deck area facing the pool talking to her friends and keeping an eye on her two children.

There was no lifeguard on duty, a coroner's court heard on Monday.

About 30 minutes later, the boys' mother saw her elder child and the other five-year-old running towards the jacuzzi area but did not suspect anything.

Her view was partially blocked by a horse-shoe shaped structure near the jacuzzi area.

Soon after, she saw the elder boy sitting on the float in the middle of the pool supporting Bing Hong whose head appeared to be floating on top of the water.

Alarmed, she asked her friend to check on her two children.

Ms Gillian Chua, 23, dived into the pool and saw that Bing Hong's face had turned blue, and that he was unconscious.

Cardiopulmonary resuscitation on the boy was carried out but to no avail.

In recording a verdict of misadventure, State Coroner Victor Yeo said young children playing in the adult pool should be watched and supervised closely at all times.

'A moment of inattention over the child could lead to disastrous consequences as this case has shown,' he added.