Here, we take a look at the transfer rules which govern each league in the winter window.
Clubs are still able to sign players as free agents after the deadline, as long as they are not officially attached to any club when the window closes, which is Jan. 31 in most leagues.
Premier League transfer deadline
The transfer market will reopen on Saturday, Jan. 1 and close at 11 p.m. GMT / 6 p.m. ET on Monday, Jan. 31.
The deadline is the same for Championship clubs, should they be looking to bring players in on loan from the Premier League.
La Liga transfer deadline
In Spain, the transfer market will swing back into action on Monday, Jan. 3.
The window will close at midnight local time (11 p.m. GMT / 6 p.m. ET) on Monday, Jan. 31.
Serie A transfer deadline
Serie A clubs will be able to start making transfers as of Monday, Jan. 3.
The January window will close at 7 p.m. GMT / 2 p.m. ET on Jan. 31.
Bundesliga transfer deadline
German clubs have set their transfer window at 5 p.m. GMT / midday ET on Monday, Jan. 31.
The window opens on Jan .1.
Ligue 1 transfer deadline
Ligue 1 will close its window on Monday, Jan. 31 at 11 p.m. GMT / 6 p.m. ET.
Clubs can start doing business on Jan. 1.
A handful of top leagues will still be able to buy players after Jan. 31. The deadlines are:
Feb. 1: Mexico
Feb. 2: Portugal
Feb. 8: Turkey
Feb. 10: Australia
Feb. 22: Russia (window opens Jan. 26)
Feb. 28: China