You're planning a trip to Cancun and wondering how many days you need to stay. The short answer is three days. The long answer is: because you'll have plenty of time to see the sights, and still get some beach time in. Cancun is a city that can be explored with plenty of time to spare, so don't worry about wasting any of your budgets by staying longer than necessary. You'll still have plenty of time to enjoy the city's miles of white sand beach, as well as its rich culture and diverse cuisine.