K-84 Ekaterinburg () is a Project 667BDRM Delfin class (NATO reporting name: Delta IV) nuclear-powered ballistic missile submarine. The submarine was laid down on 17 February 1982 at the Russian Northern Machine-Building Enterprise (Sevmash). She was commissioned into the Soviet Navy on 30 December 1985. After the collapse of the Soviet Union, the submarine continued to serve in the Russian Navy. Initially known only by her hull number, in February 1999 she was renamed after the city of Yekaterinburg.