Travelers who have completed their vaccinations at least two weeks before arrival are allowed in.
Proof of vaccination for travelers who have been vaccinated at least 2 weeks before departure will exempt travelers from the negative COVID-19 test.
Travelers must download the Belize Health App and complete the required information within 72 hours prior to boarding a flight to Belize. This will create a unique QR code for contact tracing while in Belize. A completed "Health form" must be presented upon arrival. The form can be found at https://www.travelbelize.org/health-safety/ by downloading the Belize Health App or upon arrival.
Those who test positive will be quarantined at their Gold Standard hotel at their own expense. until the Ministry of Health gives clearance.
Children under the age of 2 are exempt from presenting a COVID-19 test.
Travelers with proof of recovery from the virus within the last 90 days prior to boarding. Proof of a recent positive viral test and a letter from your healthcare provider or a public health official stating that you were cleared to travel.
More info at the CDC site
Travelers who did not get tested, are advised to stay home and self-quarantine for 10 days after travel.