Oceana, formerly Princess Cruises' 77,000-ton Ocean Princess, joined the P&O Cruises fleet in November 2002.
It coincided with the retirement from service of the company's smallest cruise liner, Victoria, and was in response to continuing growth and substantial future prospects for the UK cruise market.
David Dingle, managing director of P&O Cruises, said:
"In Oceana, P&O Cruises gains an imaginatively-styled ship, full of innovation and with a glamour and sense of fun all of her own. She will be a natural complement to the contemporary Aurora and classic Oriana.
"There is no doubt that the 2000-built Oceana will enhance further the quality of the fleet. Like Aurora she offers a higher ratio of balcony cabins for added passenger privacy while flexible 24-hour dining is just one of a wider range of passenger facilities."