We will be visiting Athens and Santorini for the first time this May 2022. Do you typically need to make reservations for most things during the month of May? I understand that popular restaurants with a view may get booked, but what about excursions such as sunset cruises, tours, etc? Should we book most things before we get there or ask for recommendations from our hotel? I really hate a vacation that is overly scheduled and prefer to have it be more relaxed, but I don't want to miss out if things get booked up. Thanks for any advice.
The only thing you really have to book ahead is your hotel reservation. Make sure the hotel has a refundable cancellation policy.
Even car rentals can be done after you arrive.
If you're staying for 4 days or more you don't have to reserve a table at one of those popular restaurants before you arrive. Have your hotel do it for you once you're there and know when you want to go. If you're there for less than that it wouldn't hurt to reserve a table before you arrive since your "window of opportunity" is shorter.