She entered civilian service in 1948 on RMSP's premier liner route between Southampton, Rio de Janeiro and Buenos Aires.

For seven years she worked the route full-time, but from 1955 the frequency of her liner voyages decreased and she spent an increasing proportion of her time cruising.

Compagnie de navigation Sud-Atlantique had two 15,000 GRT liners on the route, Lutetia (1913) and Massilia (1920), that were smaller and older but at 20 knots (37 km/h)[1] could offer a passage that was quicker by several days.

Essendon claimed that German, French and Italian competitors were running ships to South America at 22 knots (41 km/h), giving a passage about five days quicker than RMSP.

[5] He urged RML directors to have Asturias and Alcantara re-engined with steam turbines to cruise at 19 knots (35 km/h), and to order a new third ship of similar performance to augment the fleet.

[6] Directors approved the re-engining of Asturias and Alcantara, foreign competitors agreed to Essendon's voluntary speed limit, but in 1932–33 the Great Depression was acute and the Board rejected his proposal for a new ship.

[7] In February 1935 RML began to consider replacing the ageing A-series ship Atlantis, which had been transferred from liner service to cruising.

[10] After the launch, Lord Essendon complained that British re-armament had both increased shipbuilding costs and depressed the merchant shipping trade.

[11] While Andes was being built, Compagnie de Navigation Sud-Atlantique intensified potential competition by also ordering a new liner for the South American route.

She was scheduled to leave Southampton on her maiden voyage to Rio de Janeiro and Buenos Aires on 26 September, which was the centenary of RMSP's foundation.

But her sea trials were postponed, and when the UK and France declared war on Germany on 3 September the Senior Naval Officer at Belfast cancelled them.

Most of the troop ships, including Andes, left Cape Town on 30 August as part of Convoy WS 2A, which dispersed in the Indian Ocean a fortnight later.

Its forces' success was limited, but on 24 September Andes, the two Empresses, Franconia, Otranto and Strathaird left Suez in the lightly-escorted Convoy SW 1 carrying civilian evacuees.

The others were P&O's Strathaird, Strathallan, Strathnaver and Viceroy of India, Orient Line's Orcades and Otranto, CP's Empress of Canada and Duchess of Atholl and Pacific Steam's Reina del Pacifico.

One soldier who travelled on Andes recalls that when the convoy reached warmer latitudes he slept on deck under the stars to escape the crowded accommodation below.

Most of the other ships that formed SW 4B had arrived in WS 4B a fortnight earlier: Strathaird, Strathallan, Strathnaver, Viceroy of India, Orcades, Otranto and Empress of Canada.

[34] WS 14 left the Clyde on 9 December, reached Freetown on the 21st,[34] stayed until Christmas Day and then continued to South African waters off Durban, where it divided into sections.

There were also six Dutch troop ships: KPM's Boissevain, Nieuw Holland and Ruys, KRL's Indrapoera and Sibajak and Netherland Line's Johan van Oldenbarnevelt.

KMF 3 included many vessels with which Andes had sailed before, among them the troop ships Christiaan Huygens, Duchess of York, Empress of Australia, Nea Hellas, Orontes, Rangitiki, Staffordshire, Strathaird, Strathallan and Windsor Castle.

Andes returned to service in October,[20] leaving Liverpool on the last day of the month carrying 2,162 troops to New York, where she arrived on 8 November.

[20] Although Andes was built as an ocean-going ship she was designed for the temperate to tropical sea and weather conditions between the UK and South America, rather than cold North Atlantic winters.

[18] On 22 January 1948, eight years and four months after her cancelled civilian maiden voyage, Andes sailed from Southampton on her first commercial run to South America.

RML had innovated by selling 100 First Class berths to round trip passengers, who for a £10 supplement could remain aboard Andes in Buenos Aires, using her as an hotel.

Alcantara was released in August 1947, refitted for commercial civilian service and in October 1948 joined Andes on RML's South American route.

[64] In cruise service Andes' passengers included Law Lord Baron Birkett and actresses Joan Regan and Margaret Rutherford.

[64] On a cruise in June 1959 Andes visited Lisbon during a British trade fair; aboard the ship RML hosted a cocktail party at which the guests included Princess Margaret and the Portuguese dictator António Salazar.

[64] After her last ever liner voyage in November 1959 Andes sailed to Flushing, Netherlands, where Koninklijke Maatschappij De Schelde converted her into a full-time cruise ship.

The four First Class luxury suites were now named Alcantara, Almanzora, Araguaya and Asturias after famous Royal Mail liners of the past.

On the second cruise the drive shaft for the forced-draught fan to Andes' central boiler sheared, and as she left Rio de Janeiro her steering gear failed.

She entered port flying a paying-off pennant 93 feet (28 m) long, and she was dressed with signal flags that spelt out a message in Latin: Andes in opus per mare ubique 1939–1971 hodie recedere.