The 34-year-old's new contract, which includes the option of a further year, comes in the same week as midfielder Leon Britton and defender Garry Monk put pen to paper on extensions with the south Wales club.
Tremmel only made a handful of first-team appearances under Brendan Rodgers, but has deputised admirably for Michel Vorm during the current campaign and has helped the Swans reach their first major cup final after keeping two clean sheets in the Capital One Cup semi-final success over European champions Chelsea.
"Since the first day I joined this club, I knew something special was happening," said the German, who joined the club in 2011.
"I have been at a number of clubs, but the feeling here between the players, staff and supporters is different.
"I feel very, very good here. Of course, last season I didn't play the amount of games I had hoped for, but this season has been a completely different story on the pitch for me.
"I have played in a lot more games and big matches against the likes of Manchester City, Chelsea, Arsenal and Liverpool to name but a few.
"I think it has been good for myself and the supporters. I've been able to build momentum with a consecutive run of games this season, while the fans can now see what I am capable of.
"I am contributing a lot more, which is great, and when the opportunity came along to sign a new deal here I was very happy to do that.
"The club has been on a remarkable rise over the last few years, and it really is a nice story - I was keen to be a part of that story, so the new contract is great news for me because I feel I have a lot more to give this club."
Source: PA
Source: PA