Booking tickets for Greek archaeological sites

Buy from the official government portal, hhticket.gr, and not from anywhere else. Greek archaeological sites and museums sell their own tickets through it, and the resellers that outrank it in search results are adding a markup and a middleman to a transaction that works perfectly well direct. The practical tell is that a site charging a "booking fee" or "skip the line service charge" for a state-run monument is selling you the same timed entry you can buy yourself in about two minutes.

Book the earliest slot available, because at the major sites the ticket and the strategy for a Greek July are the same decision. An eight o'clock entry at the Acropolis is a materially different visit from a ten o'clock one — cooler, emptier, and better lit for photographs — and by the time the late morning slots are running you are queuing in full sun on marble that has been heating since dawn. The same logic holds at every large site: the first hour after opening is the one worth having.

Pre-buy rather than turning up, and not only for the queue. A booked slot removes the possibility that a site has sold out for the morning by the time you arrive, which in July at the busier monuments is a real risk rather than a theoretical one.

Check the gate before you drive, because some sites have more than one and they are not equivalent. At Mystras the ticket is valid at both entrances, but the two are at different elevations — and the whole experience turns on going in at the upper Kastro gate and walking down through the site rather than starting at the bottom and climbing. Same ticket, same site, entirely different day. It is worth ten seconds on a map before setting off.

Keep the confirmations offline. Screenshot the QR code rather than trusting that you will have signal and battery at the gate, since the moment you need to present it is disproportionately likely to be a moment when you have neither.