The maritime boundary between Denmark and Sweden is composed of two discontiguous lines. The longer boundary lies in the west through the Kattegat and is between the mainlands of both countries. The shorter boundary in the east divides the waters of the Baltic Sea between the Danish Island of Bornholm and Sweden’s mainland coast.

The westerly boundary is comprised of three separate sections. In the middle section, there is a territorial sea boundary in Øresund (the Sound), a strait with heavy shipping traffic, spanning 63 nautical miles (M). On either side of Øresund, two continental shelf boundaries extend into the Skaggerak, one to a tripoint with Norway in the north, and the other to a tripoint with Germany in the south, for an overall length of 180 M. The eastern continental shelf boundary with Bornholm extends for 110 M.

The territorial sea boundary was initially delimited in 1932 and updated using a modern chart datum in 1995. The continental shelf boundaries were defined through a bilateral agreement reached in 1984.