K-18 Karelia (Russian: К-18 Карелия) is a Project 667BDRM Delfin-class (NATO reporting name: Delta IV) nuclear-powered ballistic missile submarine currently in service with the Russian Navy. It was built in Severodvinsk by Sevmash shipbuilding company and was commissioned in 1989. It was refitted from 2004 to 2009, after which it returned to the navy.