Admiral Isakov was assigned to the Northern Fleet on 16 January 1971, under the command of Captain Lyudvig Agadzhanov.[12] She began her voyage to the fleet in April after receiving ammunition and completing other preparatory tasks, suffering a boiler malfunction in the Norwegian Sea on 19 April. Upon arrival in Severomorsk on 22 April, she became part of the 120th Missile Ship Brigade of the Northern Fleet's 7th Operational Squadron. Admiral Isakov shadowed a United States Navy carrier group in the Norwegian and Barents Seas between 11 August and 21 September.