Be ready for pickup at your hotel in Cancun (6:30am) or Playa del Carmen (8am). Bring a towel, swimsuit, extra clothes, and biodegradable sunscreen. Hop on the bus and relax during the ride to the Tulum ruins, arriving around 9am.
Take a guided tour of the Tulum archaeological site with a certified guide, touching on all the most important landmarks in the complex. Learn that the original name for Tulum, Zamá, means 'sunrise' in the Mayan language, appropriate for this seaside fortress on the eastern shore of the country. Spend some free time strolling the grounds and snapping photos of the impressive structures.
The tour's next stop is a local beach, where you will arrive around 11:15am. Get kitted out with snorkel gear and spend the next 45 minutes or so exploring the underwater world. Take in views of the vibrant coral reefs and resident tropical fish, then dry off on the sunny beach before heading back to your hotel for drop-off.