Carnival Corporation & plc, the world's largest cruise shipping group, has earmarked four ships for disposal this year, it said in a statement.

"Carnival Corporation & plc's fleet enhancement strategy will add two new ships to its fleet in 2015 and remove four ships from the fleet," the company said in a statement, in which in unveiled a strategic agreement with two shipyards to build a total of nine ships up to 2022.

The company has recently sold Grand Celebration, a mid-1980s built vessel of 47,262 gross tons, to a Florida based buyer to be employed on short cruises to the Bahamas. Late last year, the 1985 built Grand Holiday of 46,052 gross tons was sold for Cruise & Maritime Voyages in the UK.

Carnival group still employs several ships that are more than 20 years old. The oldest units in its fleet are Holland America Line's 1988 built Prinsendam and P&O Cruises Australia's Pacific Pearl, which is of similar vintage. Pacific Dawn and Pacific Jewel, the other two ships of the Australian company are also more than 20 years old. It will receive two Statendam class vessels from the Holland America Line fleet later this year. These early 1990s built ships will undergo a major refit before entering service with the Sydney based company.

The eight strong Fantasy class of Carnival Cruise Line was built in Finland in 1990-98, while the Sun Princess class of Princess Cruises that comprises four ships was built in 1995-2000. P&O Cruises in the UK celebrates the 20th anniversary of its 69,840 gross ton Oriana this year.

On the 2015 addition side, P&O Cruises UK officially launched Britannia, at 143,760 gross tons the largest ship ever designed exclusively for Britain, in a majestic naming ceremony earlier this month. Later this year, the AIDA Cruises fleet will welcome the 124,500 gross ton AIDAprima, which is expected to be one of the most technically advanced and sustainable cruise ships ever built, the Anglo-American company said.