Defender Tom Cruise, goalkeeper Martin Rice and young striker Ashley Yeoman have all agreed 12-month contracts with the Gulls.
The defensive duo of Aaron Downes and Brian Saah remain in negotiations with the club.
''It is nice to tick off three lads when it comes to new contracts and it adds more numbers to the squad," manager Alan Knill told the club's official website. "I also hope others see those sign and think it is time for them to do the same.
"It is a waiting game with Downes and Saah. The players have until June 10 to make their decisions and let us know, so you have to be patient.
''In the meantime, we obviously have to cover all bases and if it doesn't go well, we need to speak with other centre-halves, which is what we're doing. Like most people, they are keeping their options open."