Transfer window explained

Summer window typically runs from mid-June to early September. The January window runs the entire month of January, with deadline day on 31 January (or the following Monday if it falls on a weekend).

All four mirror the Premier League closely. Summer windows typically open in early July and close in early September; January windows run for the month of January. Exact dates vary by year and association — clubs sometimes coordinate to make the cross-border market easier.

The last day of each window is a media event in its own right — clubs scramble to finalise late deals, and announcements drop right up to the registration deadline. Paperwork lodged with the league before the deadline is still valid even if formal announcement happens later (the "deal sheet" rule in England).

A player whose contract has expired (a free agent) can be signed at any time. Players in the final six months of their contract can also sign a pre-contract with a foreign club, ready to move on a free at the end of the season.

FIFA has progressively tightened how many players a club can have out on loan internationally at one time, with the cap currently at six. Domestic loan rules vary by association.