As of today, 21st of July, there are new regulations for citizens of UK, Russian Federation and Cyprus coming to Croatia.
We would like to bring to your attention that Croatian Institute for Public Health has announced today that the citizens of the UK, Russian Federation and Cyprus coming to Croatia need to have a valid PCR or antigen test to enter the country. Even if you have been vaccinated in your country or had COVID-19 in the last 6 months you still need to have a valid test when you enter Croatia.
Full text (in Croatian, which you can google translate) can be found here: https://www.hzjz.hr/priopcenja-mediji/priopcenje-o-izmjeni-popisa-drzava-za-koje-se-pri-ulasku-u-republiku-hrvatsku-primjenjuju-posebne-epidemioloske-mjere/
As we understand the announcement, this additional requirement has come to effect in order to minimize the import of new variants of COVID-19 into the country.