The Slovenian stopper's new deal runs to 2020 and although he is happy to remain as one of the back-ups at the Liberty Stadium, he feels he now needs to experience first-team football.
“I am very happy to sign another contract here," Zabret told the Swans website. “I have been here since I was 17 and the club is like a family to me.
“There have been ups and downs since I arrived in 2013 but overall I am pleased how I have developed as a player, and I feel I am going in the right direction.
“I have a lot of good memories here and hopefully I can get many more.
“The next step for me is to continue to get game-time and progress to first-team football, whether that be here on out on loan."
Now 22, Zabret began his career at Prva Liga side NK Domzale before making the switch to the Swans in July 2013.