The Black Cats will face stern competition in the race for promotion, with a number of their third tier rivals having already completed some eye-catching deals – which could prompt some worry. Scroll down and click through the pages to see EVERY deal completed in League One this summer so far:
1. Accrington Stanley
In: Joe Pritchard (Bolton)
Out: Ben Richards-Everton (Bradford) Photo: Jan Kruger
2. AFC Wimbledon
In: Nathan Trott (West Ham United - loan), Adam Roscrow (Cardiff Met), Luke O’Neill (Gillingham)
Out: James Hanson (Grimsby Town) Photo: Catherine Ivill
3. Blackpool
In: Adi Yussuf (Solihull), Ryan Edwards (Plymouth Argyle), Sully Kaikai (NAC Breda), Ben Tollitt (Tranmere Rovers), Jamie Devitt (Carlisle United)
Out: John O’Sullivan (Morecambe), Mark Cullen (Port Vale) Photo: Mark Robinson
4. Bolton Wanderers
In: None
Out: Mark Beevers (Peterborough), Joe Pritchard (Accrington), Mark Little (Bristol Rovers), Clayton Donaldson (Bradford City), Luca Connell (Celtic), Sammy Ameobi (Nottingham Forest) Photo: Nathan Stirk