| Kanmurijima Island | |
| Map: | Japan |
| Native Name: | 冠島 Kanmurijima |
| Native Name Link: | Japanese language |
| Nickname: | Oshima or Yushima[1] |
| Location: | Sea of Japan |
| Archipelago: | no |
| Area Km2: | 0.223 |
| Length Km: | 1.3 |
| Width Km: | 0.5 |
| Coastline Km: | 4 |
| Elevation M: | 169.7 |
| Country: | Japan |
| Country Admin Divisions Title: | Prefecture |
| Country Admin Divisions: | Kyoto Prefecture |
| Country Admin Divisions Title 1: | City |
| Country Admin Divisions 1: | Maizuru |
| Population: | 0 |
| Ethnic Groups: | Japanese |
is an island in the Sea of Japan administered under Maizuru in Kyoto Prefecture. It is about 2 km from Kutsujima, a similar smaller island. is located just midway between islands. A breeding ground for streaked shearwaters, the island was designated a Japanese natural monument (天然記念物, tennen-kinenbutsu) in 1924. It has also been recognised as an Important Bird Area (IBA) by BirdLife International.[2] Currently, the island is designated as Kanmurijima-Kutsujima wildlife protection area and any landing is prohibited. A recreational diving service is available though.[3]
According to records of Tango no kuni fudoki, Kanmurijima and Kutsujima are the remains of a much larger island which submerged following an earthquake in 701 A.D. The topography of the seafloor seems to support the claim, as the steep 60-metre cliff is located underwater off the eastern coast of Kanmurijima and Kutsujima, indicating a recent crustal fault.