Regarding Pym's commitment, boss Darren Ferguson said he was "delighted" to confirm the keeper's future but said that Posh would be looking for another goalkeeper to "challenge" Pym.
He added: "We wanted to look after 'our own' in the early part of the summer and I have been really pleased that we have managed to get so many players tied down to longer contracts that we wanted to keep. Christy is a big part of the club moving forward.
"He hasn’t played in the Championship before, but we believe he is more than capable of handling that step-up. He knows there are improvements he can make to his game, but that is the same for every player. He has been excellent since he walked in the building, winning the Golden Glove and making a major contribution to last season’s success.
"It is important that we bring in another goalkeeper to really push and challenge Christy and we will be looking to do that over the summer. It has been a really good start to the summer in terms of what we have achieved so far."
Pym has made 87 appearances since joining Peterborough and is glad the run will be continuing, saying: "It didn’t take long to get sorted and I am really pleased. The season has only been finished two or three weeks so it is nice to get it all done and dusted and can look forward to some time with my family. I really like it here; we have a settled group, and we have Championship football to look forward to.
"I can now focus on what the job is next season in the Championship, it is going to be tough, but it is something that we can really be excited for. The manager had individual meetings with the players when we knew what division we were going to be in next season and made it clear what he wants from me and that was great to hear.
"I love working for the gaffer, he has been brilliant with me since I came into the building and I really enjoy training and working with the group that we have. In the past I have come so close to getting promotion, I really wanted to savour this one, yes I enjoyed the celebrations like everyone else, but I wanted to really take it all in, but that is gone now, we have a new season to look ahead too."
Defender Dan Butler also put pen to paper for a three-year deal with the team, having joined in 2019 from Newport County.
Regarding Butler's contract, Ferguson commented: "Dan is a great character; he is another one that was coming to the end of his contract, so it was important that we got it over the line. You need athletic players; Dan has been part of the backbone of this team and you are going to need character in abundance next season.
"We are delighted he has agreed. He has performed really well in a couple of different positions. He loves coming in every day, he is a big part of what we are trying to do. Credit to the chairman and the co-owners that we have managed to get it done so quickly, they, alongside Barry, have moved swiftly once we got promoted against Lincoln to get these contracts sorted."
On signing, Butler confessed it was probably the easiest decision he's made in his football career. He added: "I am really excited for the future; a lot of the boys are already signed up and we can look forward to what’s ahead.
"It is nice to get it done early, I think that suits both parties: the club so they know what is going on, but also my family. I have a young family and where we are based, we are already settled so it will be easy. I think what we achieved last season has sunk in over the last seven days or so, it is the first time I have got to see my family and friends and speak about it.
"It has hit home that I am going to have an opportunity to play in the Championship and four or years ago I would not have thought that would happen, so it feels good. I know that I have a lot of hard work ahead of me but I am looking forward to it."