Just an FYI, if there are any Catholic expats in Cancun there are a couple of great places to go to Mass in English. The Church of the Risen Christ has a 9am mass, which is the most popular. They are towards the front end of the hotel zone, ironically just across the street from the Playboy Casino.
The Moon Palace has Mass at 8:30am and then a 9:30am Mass at the Cancun Palace. Real Caribe also has a bilingual mass but I am not sure on the time. If you need more information feel free to contact me.
Craig