Mexico has so far allowed in travellers from almost anywhere without the need for testing or vaccinations or quarantine, and as a result has not suffered the big decline in medical tourism and tourism that other countries have. The downside is a high level of COVID-19 cases and deaths, and the national government is now considering travel restrictions on international arrivals.
Mexico has recorded 3.4 million Covid cases and 260,000 deaths, with both figures widely believed to be well below actual numbers. Only a third of the population has been vaccinated.
There are currently no limits on international air travel or domestic travel. Health protocols in place include temperature checks to enter some restaurants, shops and bus stations. A health questionnaire must be filled out and submitted at the airport for international and domestic travel in Mexico, but there is no comeback on people not telling the truth.
The country has no plans to implement any national vaccine mandates and/or proof of inoculation for domestic or international travellers. Some states have suggested they will bring in their own rules.
What complicates the position is that Mexico is on a Level 3 (high risk) travel health notice from US authorities. Non-essential travel at the land border between the U.S. and Mexico is restricted, but air travel remains open.
It is widely expected that the USA will soon require foreign visitors, and perhaps returning Americans, to be fully vaccinated to enter the country.
Most Mexican medical tourists are from Southern US states that have a much lower level of vaccination and much higher level of active anti-vaccination and anti-mask activity that other states.