The transfer window is the period during the year in which a football club can transfer players  into their playing staff.

The English Premier League transfer window formally opens on 1 July, transfers between clubs in the same association can take place as soon as the last competitive fixtures for the season have been played. However, many transfers will not be completed until 1 July because many players' contracts expire on 30 June.

The Mid Season Transfer windows opens from the 1st to 31st of January.

Outside of the transfer window, a club may still sign players on an emergency basis, usually if they have no goalkeeper available. Special dispensation from their competition's governing body, for example the Premier League, is required.