The Black Cats have seen plenty of players leave too, including stalwart Lee Cattermole and high earners Bryan Oviedo and Donald Love. Here, we round-up every deal the North East club has concluded during the summer. Scroll down and click through the pages to see the full list.
1. OUT: Adam Matthews
The Wales international left Sunderland in the summer and has been training with Charlton. Photo: JPIMedia
2. OUT: Ethan Robson
The midfielder has joined Grimsby Town on loan. Photo: JPIMedia
3. IN: Jordan Willis
The ex-Coventry captain signed on a free transfer in the summer. Photo: Frank Reid
4. IN: Marc McNulty
The attacker joined on loan from Reading. Photo: FRANK REID