For the standard "Self-Guided Stadium Tour" at Emirates Stadium, you can indeed just "turn up" and purchase a ticket at the desk in the Armoury Store, as these are "flexi" tickets that don't require a specific time slot. However, for a more guaranteed and smoother experience, especially during peak tourist seasons or school holidays, pre-booking online is highly recommended. Pre-booked tickets are often valid for up to three months from the date of purchase, giving you flexibility. It is important to note that "Legends Tours"—where you are led by a former Arsenal player—and the "VIP Legend Experience" must be booked well in advance as they have limited capacity and specific scheduled times. Also, always check the Arsenal website before heading out on match days; the stadium tour typically closes early or doesn't run at all on days when the first team is playing at home. If you just want to visit the Arsenal Museum without a full tour, you can also pay for entry on the spot at the museum entrance located near the Ken Friar Bridge.