Mindanao Island in the context of "Zamboanga Peninsula"

The Celebes Sea (/ˈsɛlɪbiːz, səˈliːbiz/ SEL-ib-eez, sə-LEE-beez; Filipino: Dagat Selebes) or Sulawesi Sea (Malay: Laut Sulawesi; Indonesian: Laut Sulawesi; pronounced [ˌlaʊt̪̚ sulaˈwesi]) of the western Pacific Ocean is bordered on the north by the Sulu Archipelago and Sulu Sea and Mindanao Island of the Philippines, on the east by the Sangihe Islands chain, on the south by Sulawesi's Minahasa Peninsula, and the west by northern Kalimantan in Indonesia. It extends 605 km (376 mi) north-south by 780 km (485 mi) east-west and has a total surface area of 472,000 km (182,000 sq mi), to a maximum depth of 6,220 metres (20,406 ft). South of the Cape Mangkalihat, the sea opens southwest through the Makassar Strait into the Java Sea.

The Celebes Sea is a piece of an ancient ocean basin that formed 42 million years ago in a locale removed from any landmass. By 20 million years ago, the earth's crust movement had moved the basin close enough to the Indonesian and Philippine volcanoes to receive emitted debris. By 10 million years ago the Celebes Sea was inundated with continental debris, including coal, which was shed from a growing young mountain on Borneo and the basin had docked against Eurasia.