In order to enter the Island without a visa, you should meet the below criteria.
You should have a visa to enter Vietnam. But you can visit Phu Quoc Island with no visa for 30 days.
Yes, but you need to get in touch with a local travel agent to process the extension of your visa. But there are situations where the extension request will be refused, such as when you overstayed in Vietnam or you had some problems with the Vietnam Immigration during your previous visits in the country.
Vietnam’s Ministry of Foreign Affairs has revealed an agreement between the Costa Rican Republic and the Socialist Republic of Vietnam. This is in terms of visa exemption among official or diplomatic passport holders.