From the US Embassy in Mexico website

Country-Specific Information:

As of January 13, Mexico has confirmed 1,571,901 total cases of COVID-19 within its borders since the beginning of the pandemic. Mexican authorities report widespread community transmission, thousands of cases of infection, and increased numbers of patients requiring hospitalization.   The Mexican Ministry of Health publishes daily updates on the number of cases.

Five states  are designated “red” under the federal stoplight system between January 4  and January 17 

• Baja California 
• Mexico City,
•  Mexico State, 
• Guanajuato
• Morelos

Under red, only essential activities are allowed. See more information on state-level restrictions and the stoplight system below in the “Nationwide Restrictions and Resources” section.

• The U.S. Department of State updated the Travel Advisoryfor Mexico on September 8.  Reconsider travel to Mexico due to COVID-19.  Exercise increased caution in Mexico due to crime and kidnapping.  Read the entire Travel Advisory.
• Please see the latest information about the status of consular operations including routine appointments and emergency services.

COVID-19 Testing:

Per the CDC order signed January 12, 2021, a negative COVID-19 test taken within the 3 calendar days before the flight departure, or documentation of recovery from a COVID-19 infection within the last 90 days, is required for air passengers entering the United States on or after January 26, 2021.  Please read the announcement and the CDC’s Frequently Asked Questions.  This requirement does not apply to travelers entering the United States by land or sea or to children under two years of age.  It applies to U.S. citizens, as well as foreign nationals, regardless of vaccination status.

• A negative viral COVID test or documentation of recovery is required for traveling by air to the United States, including U.S. citizens and legal permanent residents age two and over, and regardless of vaccination status.
• This order applies to all flights, including private flights and general aviation aircraft (charter flights). A negative COVID testing is not currently required for travel by land border.
• Air passengers are required to take a viral test (PCR/NAAT or antigen test for current infection) no more than three calendar days prior to their flight departure to the United States. Antibody tests are not compliant with the requirement.
• If you are arriving to the United States via one or more connecting flights, your test must be done in the three days before the first flight in your itinerary, but only if the connecting flights were booked as a single passenger record with a final destination in the United States and each connection (layover) is no longer than 24 hours long.  If your connecting flight to the United States was booked separately or a connection in your itinerary lasts longer than 24 hours, you will need to get tested within the three days before your flight that arrives in the United States.
• CDC requires that air passengers arriving in the United States have a paper or electronic copy of their test result for review by the airline before boarding and possible review by public health officials after arrival in the United States. Passengers must provide written documentation of their laboratory test result (paper or electronic copy) to the airline prior to boarding.
• Airline personnel must verify that every passenger over age two onboard has attested to receiving a negative test result or to having recovered from COVID-19 and being cleared to travel by a licensed health professional or a public health official. A parent or other authorized individual should attest on behalf of a passenger aged two to 17 years that they have received a negative test.  To see the passenger attestation, visit: https://www.cdc.gov/quarantine/pdf/attachment-a-global-passenger-disclosure-and-attestation-2021-01-12-p.pdf.
• If an air traveler has had a positive viral test in the past three months, and have met the criteria to end isolation, he or she may travel instead with documentation of positive viral test results and a letter from a licensed healthcare provider or a public health official that states the passenger has been cleared for travel. The positive test result and letter together are referred to as “documentation of recovery.”
• Airlines are responsible for enforcing the requirement for passengers on U.S.-bound flights. Airlines will deny boarding to anyone without a negative test or documentation of recovering from COVID-19.
• If you test positive, you must self-isolate and delay your travel. Do not travel until you have recovered completely from COVID-19.
• If your flight is delayed before departure, you will need to be re-tested if the delay causes your test to fall outside of the three day pre-departure testing period.
• You will have to pay for your test. You should contact your medical/travel insurance to find out if they will reimburse you.

• Testing availability in Mexico: The Secretariat of Health (Salud) maintains a list of approved laboratories (Spanish only) for viral COVID-19 testing.  Many local hospitals, clinics, and laboratories offer private testing for travel purposes.
  • The cost of PCR tests typically range from approximately 950 MXN to 4500 MXN, and the cost of viral antigen tests typically range from 200 MXN to 1000 MXN, depending on location and speed of results. Travelers are responsible for the costs of their own tests and any associated medical care.  The Embassy and Consulates are unable to administer or pay for tests.
  • S. Mission Mexico has prepared a list of private testing providers. Note: This list is not comprehensive and the information within is subject to change at any time.  The Department of State assumes no responsibility or liability for the professional ability or reputation of, or the quality of services provided by, the entities or individuals whose names appear on this lists.  Inclusion on this list is in no way an endorsement by the Department or the U.S. government.  Providers are listed by location, and the order in which they appear has no other significance. The information on the list is provided directly by local service providers; the Department of State is unable to vouch for this information.
  • Travelers visiting Mexico should contact their tour provider or hotel for more information on local testing options.
  • Please ensure that the test provider you choose will provide test results that comply with CDC guidelines (for U.S.-bound travelers) and those of your airline.
  • For U.S.-bound travelers, each state has its own testing and entry requirements. Verify what is necessary to enter the state to which you are traveling. The CDC offers testing and quarantine information on all states: https://www.cdc.gov/coronavirus/2019-ncov/travelers/travel-planner/index.html.

• The symptoms of COVID-19 (such as fever, cough, headaches, throat pain, or constant sneezing) are very similar to other respiratory diseases.  If you have mild symptoms, call your usual health care provider or the Mexican government’s hotline at 800 0044 800 or 55 5658 1111 in order to receive advice to determine whether to stay home or seek medical attention.  If you or someone in your family has difficulty breathing, please go to the emergency room or call 911 immediately.
• Individuals who were in contact with a confirmed case of COVID-19 and present symptoms of respiratory illness should follow the instructions above.  It is advisable to remain in quarantine for 14 days to prevent spreading the disease to other people.
• If you are experiencing fear, anxiety, or emotional isolation, please call the Mexican government’s hotline at 800 911 2000 for advice and support.