The summer 2017 transfer window closes for the Premier League at 11pm BST on 31 August, although signings can be completed shortly after if clubs have submitted deal sheets.
The transfer deadlines are different across Europe and beyond. For example, in Spain it finishes 24 hours after England's while in Germany it ends before.
The European Professional Football Leagues website provides a handy overview to the deadline days of the transfer window across the Continent.
For Premier League clubs in UEFA competitions they have a deadline for registrations of 11pm BST 1 September.