I already have a Flexi-Ticket, how do I pre-book entry? Pre-booking your visit online is essential for all guests. You need to pre-book a date and time of your choosing in advance. Book your time slot here. Related articles What is a Fast Track Ticket? How does the time slot system work and what time should I arrive? Can I change the date/time of my booking? How do I redeem my existing London Eye River Cruise Tickets and London Combination tickets? How do I get to the London Eye by London Underground?