The former Maccabi Tel Aviv player, who previously made seven appearances for Bayern as an understudy to Manuel Neuer, expressed his delight at making the move permanent. Peretz said: "I'm super excited.
"For the last few months this was my home, and we had so many good times and also some tense times, but even in the last few weeks with how we stayed together, you could really feel this home environment.
"That was, for me, the dealbreaker. Yes, it is my dream to play in the Premier League and on the highest stages in the world, but a bigger dream for me is to be there with Southampton. I really believe that we can be there and achieve that."