A completed "Pre-Arrival form" must be presented upon arrival. Travelers are subject to undertake COVID-19 RT-PCR upon arrival in SVG and a 5-day quarantine in a Tourism Authority/MOHWE approved Transition/Quarantine Hotel at their own expense
St. Vincent and the Grenadines has required travelers to have a medical certificate with a negative COVID-19 RT-PCR test result issued at most 5 days before arrival and complete a pre-arrival form. All travelers are subject to PCR test and quarantine upon entry.
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.