Two years can feel like an eternity to relive a bad race but it has also given national swimmer Francis Fong added motivation to seize his opportunity when he makes his SEA Games debut in Kuala Lumpur.

The 17-year-old will compete in the 50m, 100m, and 200m backstroke events in August but still regrets missing out on the biennial competition in 2015 when it was held on home soil.

Needing to clock 57.27sec in his pet 100m event at the 2015 Singapore National Age Group (Snag) Swimming Championships to qualify for the Singapore SEA Games, he fell short with a 57.45sec swim.

"I was really upset when I didn't manage to make the team. It was such a special Games to be involved in and with an exciting team," said the 1.85m, 85kg Francis, who was touted by former national coach Sergio Lopez as having the potential to be better than compatriot and multiple SEA Games gold medallist Quah Zheng Wen.

"That setback has definitely given me greater motivation to make this year's squad and the hunger to do well in KL."

The Anglo-Chinese School (Independent) student has made significant strides. His 100m back personal best is 55.85sec, set at March's Snag Championships. It is comfortably faster than the current 'A' qualifying mark and 2015 SEA Games bronze-medal time of 56.31sec.

"To make the 'A' mark shows that I'm on the right track and going faster than I've gone before," he said.

"I think the 100m back is my best chance and hopefully I'll have a positive race in Malaysia."

He is one of 10 in Singapore's 27-strong swim squad making their SEA Games debuts in Malaysia. More than half of this group are 16 or younger, with Methodist Girls' School's Gan Ching Hwee, who turns 14 this month, the youngest.

Only Francis, Ching Hwee and Teong Tzen Wei (50m freestyle) have met the 'A' marks. The other seven were given the green light based on their slower 'B' timings.

In some ways, the rookies could not have chosen a more challenging Games to make their bow.

A hostile reception likely awaits them across the Causeway, a prospect that Glen Lim admits could be "demoralising".

"I'm not very used to competing in overseas environments, and I might feel really pressurised stepping into the field of play," said the 15-year-old, who has been entered in the 1,500m freestyle and 400m individual medley.

"But our coaches teach us to have a strong mentality, and although I'm quite nervous I really want to see myself out there doing my best."

Despite the presence of Olympic champion Joseph Schooling and Olympians Quah and his sister Ting Wen in the team, the class of 2017 is largely inexperienced and there are few expectations of them matching the record haul of 23 golds from 2015.

This does not mean they will accept anything less than 100 per cent effort, said Jamie Koo, who will compete in the 50m back.

The 16-year-old added: "We're a talented and hardworking bunch, and this team expects a lot out of ourselves.

"We are just going to do our best and accept whatever result we get."