This September 18th, Guatemala opened its maritime, land and airport borders. These are the protocols for entering and leaving the country. Essentially PCR/Antigen negative test 72 hours in advance.

http://www.dgac.gob.gt/publico/protocoloapertura.pdf

By air✈️

a. Test: PCR/Antigen, in a laboratory certified by the respective country, no more than 72 hours prior to boarding the Guatemalan territory (applies only to people 10-year-old and older).
b. Fill out information on the Health Pass for Guatemala, available online at: https://sre.gt/.
c. Mask use is mandatory for people over 2-year-old (airlines must provide the person not wearing a mask). The use of masks is exempted for passengers who have certified medical contraindications for their use.
d. Do not travel if you have any symptoms of respiratory disease.

By land🚍

Foreigners

1) Required Tests: Negative PCR test, no more than 72 hours prior (applies to persons 10 years of age or older) for passengers entering the national territory.
2) Record of personal information for follow-up and monitoring.
3) Use of mask mandatory for people over 2 years old.
4) For passengers leaving the national territory must comply with the requirements of the country of destination.

By sea 🛳️

a. 24 hours prior to arrival, the ship’s authorities will send to the shipping company that agencies the ship, which in turn forwards it to the port captain’s office and the UVE via email, a preliminary declaration of maritime health and a record of the temperature of the passengers and crew for the last 24 hours and a statement that they have no suspects on board COVID19.
b. Medical and nursing personnel on board perform temperature measurement and recording of passengers and crew members on board the ship prior to arrival at the port.
c. This record is delivered along with the declaration of maritime health will be delivered at the time of official reception at the point of entry.
d. It will be signed by the captain of the ship and validated (countersigned) by the doctor on board.
e. In coordination with the harbour master, a quick risk assessment will be made according to international health regulations by answering the following questionnaire via radio.

Belice

These are the protocols for entering to Belize.

https://belizetourismboard.org/belize-covid-19-update-for-travellers/