From the USVI travel portal:
Travelers are required to provide evidence of:
a COVID-19 molecular (e.g., RT-PCR, viral or nucleic acid amplification) test from a nasal or throat or saliva swab sample taken and NEGATIVE result received (both within five days of commencement of travel to the Territory)
OR
a COVID-19 antigen (rapid) test from a nasal or throat swab sample taken and NEGATIVE result received (both within five days of commencement of travel to the Territory)
OR
a COVID-19 antibody (rapid) finger stick or blood draw test taken and POSITIVE result received (both within four months of commencement )
For molecular and antigen tests, the five-day window is related to both taking the test and receiving results; tests taken or results received outside the five-day window do not meet the requirements. Travelers are encouraged to plan testing dates so as to receive their results within the five-day window prior to travel to the USVI.