After a few weeks, Sayers began to talk to her about his sex life and sex in general, and around this time the two would play games such as tickling each other.
After a couple of months, Sayers encouraged the first victim to touch his genitals and on one occasion exposed himself to her, and also asked her to touch him, the court heard.
During a term break, Sayers contacted the first victim and asked to her meet him. During the meeting, they had sexual intercourse.
This continued about twice a week for a short time but later increased to daily, and Sayers stopped using condoms.
The other charges related to two other students at the college, including one victim who told the court Sayers had destroyed her trust in men.
Crown prosecutor Heidi Wrigley argued a sentence starting at five to five-and-a-half years was warranted given the significant harm Sayers had caused, particularly to the first victim.
There also needed to be an uplift for aggravating factors, which included the scale of his offending against three vulnerable victims, and "the planning and premeditation" involved.
Wrigley said the prisoner had disputed some of the key facts which also meant the first victim had to come to court as a witness during his trial.
Other aggravating factors included the devastating damage to the college's reputation resulting from media reports about Sayers' gross breach of trust, she said.
This was emphasised in a written statement from Papamoa College principal Steve Lindsey in which he stated staff, students and parents had "felt betrayed".
Sayers' lawyer Bill Nabney argued the Crown's starting point was too high, and his client deserved the full discount of 25 per cent for his guilty pleas.
Mr Nabney said Sayers offered $5000 reparation which he could pay straight away, and he deserved a further discount for doing so as he and his wife had limited means.
Judge David Cameron, who jailed Sayers for three years and four months, ordered him to pay $5000 immediately.
Judge Cameron said it there was significant ongoing emotional impacts for his victims, especially the first complainant.
Sayers had used his position to prey on his victims and in doing so had grossly breached their trust, the trust of their parents and the whole school community.
"You need to be held responsible, and I also need to deter you and others from committing this kind of sexually predatory behaviour against young girls," he said.