Makassar Strait
The strait between Borneo and Sulawesi, the northern leg of the Lombok routing, and its role in the Indonesian Throughflow and regional bulk trades.
The Makassar Strait runs between Borneo and Sulawesi, connecting the Celebes Sea in the north to the Java and Flores Seas in the south. In commercial routing it is the northern leg of a single diversion rather than an alternative in its own right: a laden ULCC that cannot transit the Strait of Malacca passes through the Lombok Strait and then north through Makassar toward northeast Asia.
The strait is the main pathway of the Indonesian Throughflow, the transfer of Pacific water into the Indian Ocean that carries a large part of the global thermohaline circulation through the archipelago. That gives it oceanographic significance beyond its shipping role, and the current structure is relevant to passage planning through the constriction.
It forms part of lane ALKI II in the partial system of Indonesian archipelagic sea lanes adopted by IMO resolution MSC.72(69), so archipelagic sea lanes passage applies. The full article will cover the geography and bathymetry, the Throughflow, the coal and other bulk trades loading on the Kalimantan shore, and the offshore installations in the Makassar basin.