The Echo class were nuclear cruise missile submarines of the Soviet Navy built during the 1960s.

The Echo I class had to operate in a strategic rather than anti-shipping role because of the lack of fire control and guidance radars.

The conversion involved the removal of the cruise missiles, the plating over and the streamlining of the hull to reduce underwater noise of the launchers and the modification of the sonar systems to the standard of the November-class SSNs.

The Echo II class carried eight P-6 (SS-N-3a "Shaddock") anti-ship cruise missiles mounted in pairs above the pressure hull.

From the mid-1970s, fourteen of the 29 Echo II class were converted during overhauls to carry the P-500 Bazalt (SS-N-12 "Sandbox") anti-ship cruise missile, with a range of 550 kilometres (340 mi).