A Ngee Ann Polytechnic student was in a toilet on campus last year when he took out his mobile phone and recorded a video of a man showering in a nearby cubicle.
On another occasion, the student molested a male friend who had stayed over at his home in 2019.
The Singaporean, who is now 20, pleaded guilty in a district court yesterday to one count each of voyeurism and molestation.
Details about the two victims have been redacted from court documents.
The offender cannot be named to protect his friend's identity.
Deputy Public Prosecutor Kwang Jia Min told the court that the offender got to know the first victim in 2017 and they became close the following year.
The victim stayed over at the offender's home on Aug 27, 2019, and they shared the same bed. The next morning, the offender slipped his hands into his friend's trousers and molested him.
The second victim was in Ngee Ann Polytechnic on Jan 13 last year and was showering after exercising.
The offender entered an adjacent cubicle and used his mobile phone to record a video clip of the man showering.
The victim spotted the device, which was extended beneath him from the next cubicle.
Alarmed, he shouted, and the device was retracted. He looked out and saw the offender emerging from a cubicle.
The court heard that the offender deleted the incriminating video clip and left the premises.
DPP Kwang said: "Investigations further revealed that the accused had done similar recordings before but he had deleted all the videos.
"The accused recorded such videos as he would feel aroused at the time of recording, which helped with his mood. The videos were for his own viewing."
The second victim alerted the police at around 1pm that day.
Yesterday, the court called for reports to assess the offender's suitability for both probation and reformative training.
Offenders given the latter will be detained in a centre and made to follow a strict regimen that includes foot drills as well as counselling. The youth will be sentenced next Wednesday.
For molestation, an offender can be jailed for up to two years and fined or caned. Those convicted of voyeurism face a similar sentence.