The Government physician Knut Lönnroth revealed during the Government's press conference at 16.00 on Tuesday.
Three of the infected are younger adults who have been traveling outside of Åland. The trio has no connection to each other.
The fourth person is a middle-aged person who has been infected by one of the three who have been traveling. The person was found through infection tracking.
The four whom are infected have mild symptoms, according to the Government physician.