Photo send by Katrin Fraenkler, a friend from Germany. The photo was made during her trip there in June 2018, with occasion of Postcrossing meeting. I will go this year in 2019 at same event - is yearly held. I will add photos for sure :)
Official site:
https://www.alandpost.com/
Wiki : Åland Post is the company responsible for postal service in
the Åland Islands, Finland. Åland Post has been operating separately from the
mainland postal service of Finland since 1993.[1]
Åland Post is a logistics enterprise with 250 employees. The
2017 turnover was 38.2 million euro. The business headquarters are located in
Sviby (Åland), Jomala, only a few kilometres outside Mariehamn, the only town
in Åland. Since 1 January 2009, Åland Post is a limited company owned solely by
the Åland Landskapsregering, the Government of Åland.