An 18-year-old recruit from the Basic Military Training Centre (BMTC) on Pulau Tekong attempted to swim out of the island towards mainland Singapore, in what is believed to be the first such case to have happened.
It is understood that the incident took place last December and he had made the swim attempt at night.
However, he was spotted and picked up by the Police Coast Guard and handed back to the authorities at the training centre.
The Ministry of Defence confirmed that the recruit "attempted to swim out of Pulau Tekong towards the main island of Singapore", The Straits Times reported on Wednesday.
He was found on the Kechil Land Link, a strip of land linking pulau Tekong and Pulau Tekong Kechil, said Mindef spokesman Colonel Desmond Tan.
But it is unclear how far he had swim when he was first spotted. Tan also did not give any specifics of the date and time in which the incident took place.
When, queried, Tan declined to comment on what additional measures have been put in place or whether the recruit is still in active service.
He would only say that the recruit — believed to be a science student from Raffles Institution — has been "disciplinary dealt with".
For leaving the camp without permission, he could have been declared as having gone absent without official leave, an offence under military law punishable with a jail term in the detention barracks of up to two years.
Those who knew him said the recruit kept a low profile, was soft-spoken but eloquent. He had enlisted in early December, and was then undergoing an eight-week-long programme called the Physical Training Preparatory (PTP) phase.
Recruits placed under the programme are meant to raise their physical fitness ahead of the nine-week Basic Military training programme.