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 shipping company P&O and was founded during a restructuring of P&O's operations in 1977. 

P&O (formerly the Peninsular and Oriental Steam Navigation Company) was a British shipping and logistics company dating from the early 19th century. Formerly a public company, it was sold to DP World in March 2006 for £3.9 billion. DP World currently operate three P&O branded businesses, P&O Ferries, P&O Maritime and P&O Heritage.

Along with P&O Cruises Australia, a sister company also founded by P&O, it has the oldest heritage of any cruise line in the world, dating to P&O's first passenger operations in 1837.

P&O Cruises was divested from P&O in 2000, becoming a subsidiary of P&O Princess Cruises, before coming under its current ownership in 2003, following a merger between P&O Princess Cruises and Carnival Corporation.  In 2018, the company had a 2.4% market share of all cruise lines worldwide.

According to en.wikipedia