Bartley agreed a three-year contract with the Swans after finally accepting he would have to leave the Emirates Stadium on a permanent basis to secure regular first-team action.
The 21-year-old made only one appearance for the Gunners in five years at the club and spent last season on loan at Scottish club Rangers after two previous loan spells at Sheffield United.
Bartley could make his debut for Michael Laudrup's side in their Premier League opener against QPR at Loftus Road on Saturday, subject to receiving international clearance.
Speaking to Swansea's official website he said: "I spoke to Arsene Wenger briefly last week and he said that my game-time would be at a minimum.
"For that reason, I wanted to at least go out on loan but when Swansea came in for me it was too good an opportunity to turn down.
"I do like to play football and play the game from the back, which is exactly how Swansea want to play, and that was a massive factor for me."
Source: AFP
Source: AFP