The first two Kirby approached were offered jobs.
Kirby told both they would be able to earn about $200 working for him.
They ceased contact with Kirby after it became apparent he was referring to performing sexual acts.
The third student Kirby approached was contacted by the 30-year-old through Facebook. The pair met up during the first week of April, where Kirby performed an indecent act on the teen and paid him.
Judge Denys Barry said this was the most significant offence, but noted that the teen turned 16-years-old about six weeks after the incident.
Kirby's lawyer, Mr Paul Paino, and Judge Barry noted submissions and a letter from the 30-year-old demonstrating that he had deeply regretted his actions and their impact on his victims.
He had also enrolled himself with the Lower Hutt WellStop sexual rehabilitation programme and made an early guilty plea to police, the court heard.
Kirby, who was abused as a child, has been forbidden to associate or contact anyone under the age of 16 years unless the meeting has been approved by his probation officer and is supervised.
He is also prohibited from contacting or associating with his victims.