We did not stay at Mayan, but I know it well.
Our kids were alittle older, youngest was 13.
Find a spot on the beach w/o seawall and just enjoy swimming. Or walk north down the beach to the park area, nice wadding and swimming from the beach. Saw some large star fish. The local little kids were making sand torilla's on the benches.
We snorkeled with a guide several times, at Hol Chan and Shark Ray alley, and Mexico Rocks. After
the kids are tired out, for several hours.
Best was our trips way north with a guide and boat, to fish and just hang out on the beach, watching all the sea life in the shallow ponds, taking our lunch with us. They voted 3 times to do that trip. Leaving about 9 am returning near sunset.
In town the boys loved the video game rooms in the afternoon and evenings. Two on front street one is in Mannalley's.
One day a trip to Caye Caulker to kick around.
Touring the island two half days on a rented golf cart.
Played some volley ball.
They hooked up with a couple local younger kids, that they enjoyed chatting and playing video games with, and we took them to eat with us a few times. Sharing life on the island and US.
Great fun, take good strong flash lights, and walk the piers at night, spotting all kinds of sea life in the water. Amazing what you can see at night off the piers.
Twice down to Barefoot's water park for kids which is a good long walk south.