Croatia open to those who are vaccinated or test Croatia is already open to visitors from around the world, with just a few requirements. For those coming from the US, you’re eligible to enter without having to quarantine if: You’re fully vaccinated, meaning it has been at least two weeks since your last recommended dose You present a negative PCR test result taken no more than 48 hours prior to arrival in Croatia, and if your test is older than 48 hours, you can get tested upon arrival and just quarantine until you get a negative result; if you stay in Croatia for an extended period of time, you’ll have to get tested again on your tenth day