Slam Dunk Festival is back for 2026, and this year’s edition feels extra special. The festival is once again hitting both Hatfield Park in Hertfordshire on Saturday 23 May and Temple Newsam Park in Leeds on Sunday 24 May over the late May bank holiday weekend. Organisers are marking a milestone with the 20th anniversary of the festival, so you can expect a full weekend of big names, new surprises, and plenty of party vibes.