I recently visited Cancun, Mexico and this was my experience. I am a US citizen with a US passport flying in from the USA. 

Entering Mexico: 

Your Airline will require a health declaration as part of check-in process. Mexico does not currently require vaccination or a negative COVID test for entry from the United States. 

Mexico requires each person complete a Tourist Card: https://www.cancunairport.com/tourist-card.html
  • Be sure to pay attention to how they want the date DAY / MONTH / YEAR
  • Be sure to DOWNLOAD when you complete it. Then click New Application for the next person in your travel party. 
  • The download will give you a PDF to print. Print both pages and keep them together. 
  • You will present the PDF to the Immigration officer. They will tear off one side and give it back to you. Keep this safe. You'll need it to leave the country. If you lose it, it's around $60 to replace it. 
The Mexico Health Questionnaire is filled out upon arrival if needed.

As a reminder, here's how to find your pre-arranged transfer at Terminal 4: 


Return to USA 
When you arrive back at the Cancun airport to fly home, you'll need: 
  • The immigration paper from your arrival 
  • A screenshot of the QR code from Vuelas Guro
  • A digital or printed copy of your negative COVID test results or documentation of recovery
  • A completed health attestation form through the airline
A screenshot of the QR code from Vuelas Guro - Before you leave, set up an account at: https://www.vuelaseguro.com/login You only need one account for your travel party. 

Log in 12 hours before your departure time. You'll need your flight information. Fill out the form.  Then, you can "Add Companion". After you add all your travel companions, you will be able to see the QR codes. Screenshot these. On our trip, they did not ask for them. In the past, we had to present them before entering the line for airport security. 

Negative COVID test results - The United States requires proof of a negative COVID test taken no more than one day before your flight back to the USA or documentation of recovery. You can read the full details of the documentation needed by clicking here.  You will show the test results to the airline employee when you check-in in at the airport. You will not be able to check-in in online and use a mobile boarding pass in Cancun. 

Health Attestation Form required by the USA 
Most airlines have this online now. 
United: During Check in Process

Depending on the airline, they may recommend you screenshot the confirmation of completing the attestation.

All these processes are requirements are subject to change.