The 2025 summer transfer deadline day for Premier League, EFL, LaLiga, Bundesliga, Serie A, and Ligue 1 clubs is on Monday, September 1. The transfer window closes at 7 PM BST (British Summer Time) / 2 PM ET on that day. After the deadline, there is usually a short grace period during which clubs can finalize deals if paperwork was submitted before the deadline. The Women's Super League transfer window closes a few days later on Thursday, September 4, at 11 PM.
In general context, "Deadline Day" refers to the final day of the transfer window in football (soccer), a hectic and busy day where clubs try to complete last-minute player signings before the window shuts.
