Iberia departed London on her maiden voyage on 28th September  1954.

 

On 27th  March 1956, while on her standard itinerary from London to Sydney and offshore of the island of Sri Lanka, she collided with the tanker Stanvec Pretoria, resulting in a gash amidships in her upper port decks, as well as damage to the bow of Stanvec Pretoria. Fortuitously, neither of the ships was put in danger of sinking. It was only after 17 days of repairs at Sydney that Iberia resumed on her normal schedule.

 

Along with Chusan, Iberia was refitted in 1961 by John I. Thornycroft & Company in Southampton, Hampshire, UK, where she was fitted with air conditioning. Just a few months later Iberia had a blackout near Auckland, New Zealand, and in 1962, grounded again in the Suez Canal, damaging her port screw. As the ship was leaving Auckland harbour, salt water got into the pipes of the cooling system and one electric generator broke down. After one week in Auckland they were given permission by Lloyd's of London to proceed without air conditioning to Honolulu where a new generator would be waiting. In 1964, her port stabilizers (a technology pioneered by Chusan) broke down, causing her to nearly roll over. Through the rest of her working life, Iberia continued to suffer one accident after another.

 

On 10th June 1966, her turbine couplings failed off the coast of Kobe, Japan, and in 1967, in Funchal, Madeira Island, Portugal, she collided with a dock. In 1968, in the same port, Iberia suffered the same blackout incident she had had in Auckland, New Zealand. P&O switched the London-Sydney route to a Southampton-Sydney route, and on her first run from Sydney to Southampton, Iberia caught fire, went through a third electric blackout, had an engine failure, and suffered a fuel leak. At Southampton, she was temporarily laid for repairs. In 1969, she had a second stabilizer breakdown. In 1971, Iberia sailed on a last voyage from Southampton to Sydney. Because of her frequent breakdowns and mechanical problems, Iberia was taken out of service in 1972, a year earlier than Chusan and Himalaya. In October 1973, she was scrapped in Kaohsiung, Taiwan, alongside Chusan.