Blup Blup Island is a small forested island of the northern coast of Papua New Guinea about 30km offshore from Cape Girgir and is considered part of the Schouten Islands. It is located at Latitude S 3°30'46" and Longitude E 144°35'16". The island is part of the Papuan province of East Sepik.

The island is volcanic (a stratovolcano) and a weak thermal area exists on the north west coast. The island is only 3.5km wide with an irregular coastline and ancient lava flows. It is thought that Blup Blup last erupted in the Holocene Period. Fresh water is available on the island from wells. Other islands in the vicinity include Kadovar and Vial Island. There is a small islet about 200m off the south-west shore of the island called Mut Mut where there is a Geodetic monitoring facility.

The island is inhabited by people called Blup Blup Islanders. The head-teacher at the island's school appears to serve many leadership functions and is called Stanley. The population of the island has not been established.