Molucca Sea in the context of Molucca Sea Collision Zone

The Gulf of Tomini (Indonesian: Teluk Tomini), also known as the Bay of Tomini, is the equatorial gulf which separates the Minahassa (Northern) and East Peninsulas of the island of Sulawesi (Celebes) in Indonesia. The Togian Islands lie near its center. To the east, the Gulf opens onto the Molucca Sea.

North Maluku (Indonesian: Maluku Utara; Indonesian pronunciation: [maˌluku (ʔ)uˈt̪ara]) is a province of Indonesia. It covers the northern part of the Maluku Islands, bordering the Pacific Ocean to the north, the Halmahera Sea to the east, the Molucca Sea to the west, and the Seram Sea to the south. It shares maritime borders with North Sulawesi and Central Sulawesi to the west; Maluku (province) to the south; Southwest Papua to the east; and Palau to the north. The provincial capital is Sofifi, mostly part of the city of Tidore Islands on the largest island of Halmahera, while the largest city is the island city of Ternate. The population of North Maluku was 1,038,087 in the 2010 census, making it one of the least-populous provinces in Indonesia, but by the 2020 Census the population had risen to 1,282,937, and the official estimate as at mid 2024 was 1,355,620 (comprising 694,630 males and 660,990 females).

North Maluku was originally the centre of the four largest Islamic sultanates in the eastern Indonesian archipelago—Bacan, Jailolo, Tidore and Ternate—known as the Moloku Kië Raha (the Four Mountains of Maluku). Upon Europeans' arrival at the beginning of the 16th century, North Maluku became the site of competition between the Portuguese, Spanish and the Dutch to control trade. In the end, the Dutch emerged victorious, beginning three centuries of Dutch rule in the region. The Japanese invaded the region during World War II, and Ternate became the center of the Japanese rule of the Pacific region. Following Indonesian independence, the region became a part of the province of Maluku.

The Sangihe Islands (also spelled "Sangir", "Sanghir" or "Sangi") – Indonesian: Kepulauan Sangihe – are a group of islands that constitute two regencies within the province of North Sulawesi, in northern Indonesia, the Sangihe Islands Regency. The word Sangihe actually comes from the word Sang Ihe which is means Strong Sailor or Brave Fisherman. Kabupaten Kepulauan Sangihe) and the Sitaro Islands Regency (Kabupaten Siau Tagulandang Biaro). They are located northeast of Sulawesi between the Celebes Sea and the Molucca Sea, roughly halfway between Sulawesi and Mindanao, in the Philippines; the Sangihes form the eastern limit of the Celebes Sea. The islands combine to total 813 square kilometers (314 sq mi), with many of the islands being actively volcanic with fertile soil and mountains.

The main islands of the group are, north to south, Sangir Besar (or Sangir Island), Siau (or Siao), Tagulandang, and Biaro. The largest island is Sangir Besar and contains an active volcano, Mount Awu (1,320 meters (4,330 ft)). Tahuna is the chief town and port, also hosting the islands' sole airport, Naha Airport.