And while Portsnouth have been slow to get off the mark in January, a host of their rivals have wasted no time in adding to their ranks with some eye-catching deals.
Scroll down and click through the pages to see EVERY deal done in League One this month:
5. Bristol Rovers
In: Jayden Mitchell-Lawson (Derby County - loan), Josh Barrett (Reading), Jamal Blackman (Chelsea - loan), Josh Ginnelly (Preston North End - loan) | Out: None Photo: Alex Davidson
6. Burton Albion
In: Jamie Murphy (Rangers - loan), Joe Powell (West Ham United), Connor Shaughnessy (Leeds United - loan) | Out: Liam Boyce (Hearts) Photo: Clive Mason
7. Coventry City
In: None | Out: None Photo: Linnea Rheborg
8. Doncaster Rovers
In: Devante Cole (Wigan Athletic) | Out: Alfie May (Cheltenham Town), Ian Lawlor (Scunthorpe United - loan) Photo: George Wood