|The Southern Cross was sold to Greece-based Ulysses Lines in January 1973. Renamed SS Calypso, the ship sailed to Piraeus where she was converted into a dedicated cruise ship. The original interior layout was retained with the exception of the indoor pool, which was replaced by a disco, whilst all interior furnishings were replaced with fashionable minimalist chrome-and-plastic creations, to conform with the then newest SOLAS regulations. Additionally, the cabins were refitted so that all now featured private bathrooms. This meant a slight reduction of passenger capacity, from the original 1,160 to 1,000.
Painted in cruise-like whites with an attractive blue/white funnel, Calypso entered service for Ulysses Lines in March 1975, initially cruising around the Mediterranean with Piraeus as the origin. After a few months she was chartered to the UK-based Thomson Cruises, to commence cruising from Tilbury and Southampton. Thomson withdrew from the cruise business in 1976 and Calypso returned to Ulysses Lines, who used her again in the Mediterranean, as well as for a season around South America in 1978-1979. Seven-night cruises from Miami to the Caribbean featured from 1979 onwards. At some point, Calypso also cruised from New York to Bermuda. In 1980 the ship was renamed SS Calypso I and used for cruises from Los Angeles to Alaska.