His love for water sports blossomed when he began going for swimming lessons with his younger sister when he was seven years old.
Mr Koh Kah Wei went on to achieve accolades in swimming, diving, triathlons and his favourite sport, kayaking.
The 30-year-old was in his kayak last Saturday when it hit driftwood and overturned in a river in Perak, Malaysia. His friends tried to help him but he was swept away by strong currents.
His body was found the next day with his shirt stuck between rocks in Sungai Tesong - about 1km from where he fell into the river.
Mr Koh's family paid tribute to him yesterday at his wake in Anchorvale Drive.
His 64-year-old father, Mr Koh Heng Choy, said his only son loved the outdoors.
To enable him to pursue his passions, the elder Mr Koh, who is a lorry driver, used to work part-time as a cabby so that his son could attend swimming and kayaking lessons. In recent years, his son attained a powered pleasure craft driving licence.
"He was very fit - he had many certificates and medals, and also ran marathons," he said. "Whatever he liked to do, as parents, we supported him."
Mr Koh's mother, a housewife, sobbed as she spoke to relatives yesterday after his sister and his girlfriend of more than three years returned home from Malaysia in the morning with his body.
He was a volunteer trainer at the People's Association Water-Venture, which conducts water and adventure sports activities, since 2010.
About two months ago, he left the job and started conducting life-saving and swimming courses.
"He believed in 'safety first'. He was found with his helmet still on, but his life vest was gone," said his father. "Maybe it was caught between the branches... it's fate."
Mr Koh had kayaked in Perak several times before.
Mr Melvyn Leong, 28, who met Mr Koh about eight years ago through a kayaking group, said: "He taught life-saving and swimming but unfortunately, he could not save his own life at the very last moment."
The licensed craft engineer added that Mr Koh was a friendly and jovial person, respected as the leader in group kayaking expeditions. "While kayaking, he would look after the safety of the group by paddling back and forth just to make sure everyone was well."
Mr Koh's father said: "He was going to earn enough money to get married... I thought he would take care of me when I grow old, but he was taken away in his prime."
Correction note: This story has been updated for clarity.