The Indian high commissioner to the United Kingdom, Vijayalakshmi Pandit, commissioned her as INS Vikrant on 4 March 1961 while she was still at Belfast, Northern Ireland. Captain Pritam Singh was the first commanding officer of the carrier. She formally joined the Indian fleet at Bombay on November 3, 1961, when she was received at Ballard Pier by Prime Minister Jawaharlal Nehru and other high-ranking dignitaries.
Her initial airwing consisted of British Hawker Seahawk fighter-bombers and a French Alize anti-submarine aircraft. On May 18, 1961, the first jet landed on board, piloted by Lieutenant (later Admiral) R H Tahiliani.
In 1965, Pakistan claimed that they had sunk her. At the time, however, Vikrant was under refit in the drydock. Despite a crack in a boiler, she saw real combat against Pakistan in the 1971 Liberation War of Bangladesh. She was considered important enough by the Pakistanis that they sent the submarine Ghazi all the way to the Bay of Bengal to mine the Visakhapatnam harbor in an attempt to sink the aircraft carrier when she put to sea. During Vikrant earned two Mahavir Chakras and 12 Vir Chakras.
Vikrant was given an extensive refit, including new engines and modernization between 1979 and January 3, 1982. Between December 1982 and February 1983 she was refitted again to permit her to operate Sea Harriers. After the retirement of the Alize propeller-driven anti-submarine planes from carrier service in 1989, she received a ski jump for more efficient use of her Harriers.
Vikrant was India's only carrier for over 20 years, but by the early 1990s she was effectively out of service because of her poor condition. Even following major overhauls she rarely put to sea. She was formally decommissioned January 31, 1997 and will be preserved as a museum at Mumbai.