The 21-year old Wales youth international has been with the Swans senior squad since 2009 and with his stay set to end next summer has now penned a three-year contract.
"I'm very happy to have signed a new contract," he told Swansea's official website. "It gives me stability as I have the next three years to continue progressing here.
"It's also reassuring knowing that the club see something in me and believe that I can grow as a goalkeeper.
"But the hard work starts now for me. I want to become a bigger part of the manager's plans and I have to keep improving every day in order to do that."