The area of the Pomeranian Bight and Arkona Basin is situated between Denmark, Germany, Poland and southern Sweden west of the island of Bornholm. The area is subject to many uses and interests, such as shipping (with many ferry connections passing this area), offshore wind energy developments, sand & gravel extraction, pipelines & submarine cables, while at the same time being significant for nature conservation, fishery and tourism. BaltSeaPlan Report No 9 “Developing a Pilot Maritime Spatial Plan for the Pomeranian Bight and Arkona Basin” not only lays out the draft transboundary spatial plan developed jointly by an international working group, but also shows the challenges and possible solutions of a process involving five planning areas subject to different interests and planning cultures as well as varying availability of background information.