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:
17. Rochdale
In: Tyler Smith (Sheffield United - loan) | Out: None Photo: Charlotte Tattersall
18. Rotherham United
In: Hakeeb Adelakun (Bristol City - loan) | Out: Joshua Kayode (Carlisle United - loan) Photo: George Wood
19. Shrewsbury Town
In: Josh Vela (Hibernian), Sam Hart (Blackburn Rovers - loan) | Out: Anthony Grant (Swindon Town) Photo: Gareth Copley
20. Southend United
In: None | Out: Tom Hopper (Southend United), Simon Cox (Western Sydney Wanderers) Photo: Tom Dulat