P&O Cruises is a British cruise line based at Carnival House in Southampton, England, operated by Carnival UK and owned by Carnival Corporation & plc. It was originally a subsidiary of the freight transport company P&O and was founded in 1977. Along with P&O Cruises Australia, another former subsidiary of P&O, it has the oldest heritage of any cruise line in the world, dating to P&O's first passenger operations in 1837.

Carnival Corporation & plc is a British-American cruise operator with a combined fleet of over ninety vessels across nine cruise line brands and one joint venture with China State Shipbuilding Corporation (CSSC). A dual-listed company, Carnival is composed of two companies – Panama-incorporated, US-headquartered Carnival Corporation, and UK-based Carnival plc – which function as one entity. Carnival Corporation is listed on the New York Stock Exchange, whereas Carnival plc is listed on the London Stock Exchange with an ADR listing on the NYSE. Carnival is listed in both the S&P 500 and FTSE 250 indices.