Family sites

Heading to tulum in April and was looking to check off two boxes. 1. bring my teenager snorkeling while my youngest and wife kicked back on a beach nearby. 2. Seeing some ruins. We are there for a week and don't mind spending a bit for a better experience. Recommendations? Wife is fairly leary on leaving the all inclusive we are staying at, so I'm trying to build a case for exploring a bit. Youngest is 7 but she's swam with dolphins and stingrays before. And the teenage has some light experience snorkeling in the ocean with me before.