Sibolga Bay (formerly known by the Dutch Baai van Tapanoeli, literally The Bay of Tapanoeli; alternatively Tapanuli Bay) is a natural harbour on the west coast of North Sumatra, Sumatra, Indonesia. It is named after the city of Sibolga which is located inside of the bay. There are a few islands in the bay, one of which was formerly the site of a fort controlled by the English and the Dutch.