All visitors and returning citizens to Saint Lucia must complete a Pre-Arrival registration form prior to arrival. Reservations for either a Government operated quarantine facility or a COVID-19 certified property must be confirmed before travel.
All arriving passengers will be screened, including temperature checks, at the airport. Any symptomatic passengers will be isolated and tested. All visitors will be required to remain in quarantine/isolation at their hotel or Government Operated Quarantine Facility until the test result is obtained. If the test is positive, all visitors and nationals will be transferred to a treatment facility until they receive two negative test results and are clinically stable.
All travelers and airline crew must have a medical certificate with a negative PCR test result for COVID-19, issued within 7 days of departure.
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.