Kapellskär is served by frequent ferry services from Mariehamn, Åland (three services every day), from Naantali, mainland Finland, and from Paldiski, Estonia. Naantali and Paldiski lines do not accept pedestrians; an accompanying vehicle is necessary to board these lines.
From the city centre, take the 676 local bus from the bus terminal adjacent to the Tekniska högskolan T-bana station and travel all the way to the terminus Norrtälje. From there, a connecting 631 or 631X service takes you to the port. Travel time from the city centre is 1h 45min.