Closed since 2015, awaiting disposal
Her keel was laid down on 10 April 1971 at Sudomekh Shipyard of Leningrad. It was launched on 22 June 1971 and commissioned on 4 December 1971.
For twenty-two years B-427 patrolled the Pacific, protecting the ballistic missile submarine bastions of the Pacific Fleet while based out of Vladivostok, Russia with the exception of a few temporary postings as part of the Soviet Submarine Squadron that was for a time based at the former US Navy base at Cam Ranh Bay, Vietnam. Such postings were normally for a period of between 8 to 12 months before returning to Vladivostok.
In 1989, B-427 was returning to Vladivostok from Vietnam when it ran into a typhoon. A mechanical breakdown that could not be fixed in time prevented the sub from diving. The storm battered the boat, destroying the light hull and damaging the ballast tanks and high pressure air bottles. B-427 was taken back to Vladivostok where it was repaired and refitted with a new light hull.
The submarine was decommissioned by the Russian Navy in December 1994. She was one of the last three Foxtrot class submarines to serve in the Russian Pacific Fleet. The boat was acquired by a group of Australian businessmen on a three-year lease purchase contract, and was towed from Vladivostok on 25 July 1995. En route to Sydney, the tow company claimed that the deal for the Russian Navy to cover the cost of the tow was invalid, and claimed that A$150,000 in towing expenses was required. The submarine arrived in Sydney on 31 August, and after some modifications, was loaned to the Australian National Maritime Museum for display as a museum vessel under the designation "Foxtrot-540" (the submarine's last pennant number while in service). As the submarine was still the property of the Russian Navy for the duration of the lease, an Australian ex-submariner was commissioned into the Russian Navy to command and look after Foxtrot-540, with the boat's former engineering officer assisting. The submarine was in near-operational condition; the diesel generators and electrical storage system, ballast tanks, and hotel load equipment were functional, and Russian personnel travelled to Australia to teach museum staff about maintenance and operation of the boat. Foxtrot-540 spent three years berthed at the museum, attracting over 700,000 visitors during this period (including intelligence analysts from multiple nations during the first weeks on display).
In May 1998, the submarine was loaded onto a heavy lift ship and relocated to Long Beach, California, sailing from Sydney on 31 May and arriving on 25 June. On arrival, she was berthed next to RMS Queen Mary, and opened to the public on 14 July under the designation "Podvodnaya Lodka B-427 Scorpion". On 19 April 2011, the company operating Queen Mary (Delaware North) announced that they had acquired Scorpion, and were planning to increase attendance at both attractions through combined ticketing and joint marketing campaigns. The Scorpion Submarine is currently owned by NEWCO Pty Ltd LLC and is on a long term lease to the Queen Mary.