Updated
As of February 25th, 2022, all COVID-19 prevention measures at the Icelandic border came to an end and apply to both vaccinated and unvaccinated visitors. (Visa requirements, however, have not changed).
Everybody is welcome: if you are planning on visiting Iceland you’ll no longer have to worry about getting a PCR test before boarding the aircraft, antigen tests upon arrival or compulsory quarantine. On top of that, you won’t have to show any kind of vaccination certificate or proof of prior COVID-19 infection.