All passengers of five years and older must now have a negative result from a PCR test taken no more than five days before arrival. The previous requirement was a test taken within seven days before travel.
The island had 1,062 confirmed cases of the virus at the end of January.
Tourism minister Dominic Fedee said: “In order to co-exist with Covid, we must constantly evaluate our safety and travel protocols.
“In due consideration of all factors affecting the health of Saint Lucian citizens and international visitors, we are tightening testing protocols based on our current conditions.”
Visitors must also submit a Travel Registration Form, found at StLucia.org/Covid-19.
Mandatory screening and temperature checks are carried out at ports of entry and transfers must be by certified taxi to Covid-approved accommodation.
Mask wearing is compulsory in public places.
