Tanfiliev is an uninhabited island in the Habomai Islands, part of the Lesser Kuril Chain. It is administered by the Russian Federation as part of Yuzhno-Kurilsky District, Sakhalin Oblast. It is claimed by Japan, as part of Hokkaidō's Nemuro Subprefecture. The island and its surrounding waters form part of the Malye Kurily zakaznik or Lesser Kurils State Nature Preserve.

The Habomai Islands are a group of uninhabited islets in the southernmost Kuril Islands. They are currently under Russian administration, but together with Iturup (Etorofu), Kunashir (Kunashiri), and Shikotan are claimed by Japan.