Cozumel is an Island in Caribbean Sea just off Yucatan Peninsula. It is mainly visited as day trip from Playa Del Carmen (45 minute boat ride) and as Cruise Ship destination. I spent a week here in Dec '18 wishing to acclimatize to tropical conditions prior to Central America trek.
North part of the Island is mostly undeveloped. South tip has Punta Del Sur ecological reserve while most of the beaches are on east side. Downtown San Miguel has lovely waterfront and several photo friendly spots. San Gervasio Mayan ruins are well worth the visit (possible to cycle from San Miguel).