The Strategic Defence and Security Review in October revealed HMS Ocean or aircraft carrier HMS Illustrious would be scrapped.
Mr Fox said HMS Illustrious would be withdrawn in 2014.
A Ministry of Defence study said amphibious assault ship HMS Ocean was the most effective helicopter platform.
A ministerial statement said HMS Illustrious would be withdrawn from service once HMS Ocean had been refitted.
Four Devonport-based frigates, HMS Chatham, Campbeltown, Cumberland and Cornwall will be withdrawn in 2011.
Chatham will be withdrawn from service at the end of January and Campbeltown and Cumberland will follow on 1 April.
HMS Cornwall will be withdrawn at the end of April once it has returned from a deployment to the Indian Ocean.
HMS Ocean, built in the mid 1990s, is designed to support amphibious landing operations.
Its secondary roles include training, anti-submarine warfare and a base for anti-terrorist operations.

The second instalment of the drama has already begun filming in Australia, with Elisabeth Moss reprising her role as detective Robin Griffin.
Christie, who has also appeared in Star Wars: The Force Awakens, said she "could not feel more privileged" to be joining the cast.
The first season of Top of the Lake was broadcast on BBC Two in 2013.
The six-part series won an Emmy award for outstanding cinematography for a miniseries and Elisabeth Moss won a Golden Globe for best actress in a miniseries.
The show is directed and co-written by Jane Campion - one of only four women to have been nominated for the best director Oscar.
Christie, who plays Brienne of Tarth in Game of Thrones and Captain Phasma in Star Wars, will have a major role in the programme.
She said: "Jane Campion has been a major creative influence throughout my life.
"I could not feel more privileged to be working on the next instalment of unique and enthralling drama."
No specific details have been released about the character she will be playing.
Elisabeth Moss, who has also starred in Mad Men and The West Wing, said: "I'm so excited to be back in Australia working with Jane on exploring this wonderful character.
"I can't wait for audiences to see where we take Robin's journey".
David Dencik, Alice Englert and Ewen Leslie will also appear in the the show's second season.
Top Of The Lake: China Girl will pick up four years on from the ending of the first series, and will see Moss's character try to solve a case after the unidentified body of an Asian girl washes up on to Sydney's Bondi Beach.
The new series will be co-directed by Ariel Kleiman and will consist of six hour-long episodes.
Filming for the series commenced in Sydney on Monday, with the show expected to premiere on BBC Two in 2017.

For a second time, he's giving up a role he didn't inherit, but gained on merit.
After stints in the RAF and the air ambulance, his days as a pilot are coming to an end.
He will miss them.  He's spoken of how he's loved working in a team. Something, he said, "his other job" didn't necessarily offer.
The prince is the only senior royal to have a deep understanding of the National Health Service the majority of the population experience.
With his family moving from Norfolk to London, Prince George will go to a private school from September.
And Prince William and his wife will be available to do more royal work.  The demands will increase now the Queen has turned 90.
The future king's exclusive focus will very soon be on his role as a Windsor and a destiny he'll one day embrace.
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The Royal Navy's largest ship, Devonport-based HMS Ocean, will remain in service, Defence Secretary Liam Fox has said.
[NEXT_CONCEPT]
Game of Thrones star Gwendoline Christie is to appear in the new series of Top of the Lake.
[NEXT_CONCEPT]
This will not have been an easy decision for Prince William to make.