Fabianski was keen on remaining in the Premier League having turned down a new contract with the Gunners and had several offers on the table.
"If I'm completely honest, the main reason I came to Swansea was because I want to be the No1 goalkeeper," said Fabianski. "I want to play week-in, week-out.
"It's going to be a real fight, but I'm not afraid of that. Competition is always good, so I think everyone will take positives from that.
"I'm excited. I've already asked for the pre-season programme to see how it looks. I'm really looking forward to starting with my new team-mates and I think it's going to be a fantastic new chapter in my life.
"I will be working hard for the club, giving everything every single day. I can promise that. I know quite a bit about [Swansea] already, but I am sure I will get to know quite a bit more in the coming months. For me, it was an easy decision to make to join the club."
For the big stories and the banter follow us on Twitter: @tribalfootball