He has gone back to issue a fresh appeal for information about her killing.
No-one has been convicted of the murder of Mrs McAreavey, 27, the daughter of Tyrone gaelic football manager Mickey Harte.
Mr McAreavey arrived at Mauritius International Airport shortly after 09:00 BST on Saturday.
With him was his sister, Claire McAreavey, who is a lawyer, and Mark Harte, one of Michaela's brothers.
'I don't want sympathy, I want justice'
She was strangled to death at a luxury hotel in northern Mauritius 12 days after her wedding in County Tyrone, Northern Ireland.
Before leaving for Mauritius, Mr McAreavey told the BBC he was prepared "to go to the ends of the earth to ensure that justice is achieved for Michaela".
He added: "We need to appeal to the people of Mauritius, so we felt that the best way to achieve that is to get on a plane and get out there."
John and Michaela McAreavey went on honeymoon to Mauritius in January 2011. She was found dead in a bath at the four-star Legends Hotel, after returning to her room to collect a packet of biscuits.
Two hotel workers - Avinash Treebhoowoon and Sandip Moneea- were later accused of murdering her and stood trial in the Mauritian capital Port Louis.
They were found not guilty of the murder.
Mauritian police launched a fresh investigation following the trial, but it came to nothing.
In Mauritius, there is some surprise that Mr McAreavey has returned to the island.
"I think people will be shocked because we gathered that he had started a new life and that he would move on and forget about this tragedy," Nad Sivaramen, a journalist with l'express newspaper said.
"People will be surprised to see him and to see that his quest for the truth is still there."
Mr McAreavey remarried in September last year. His wife, Tara Brennan, is an accountant from County Kildare.
He said: "I'm very, very fortunate that I've such a loving family.
"You move forward with life, you enjoy the good things, but you don't shy away from the hard things either."

The company has made an all-stock deal worth as much as $2.8bn (£1.9bn).
Tesla shares fell 10% in extended trading after the announcement while SolarCity jumped 23%.
California-based Tesla is known as a pioneer in electric cars but since last year has also been selling batteries that can power homes and businesses.
Tesla chief executive Elon Musk described the deal as a "no brainer".
He said it would transform Tesla into the "world's only vertically integrated energy company offering end-to-end clean energy products", from solar panels and home storage batteries to electric vehicles.
Elon Musk is under serious pressure to make Tesla profitable. The path to that goal is two-fold. The cars may eventually bring in serious money, but the outlay needed to fund the manufacture of the vehicles is far greater than what sales are bringing in.
But while Tesla is considered to be a carmaker first and foremost, the real money might be in selling energy technology. Its enormous Gigafactory, opening this summer, will be able to make batteries for much more than cars.
The SolarCity purchase was always on the cards. Musk is already the firm's chairman and biggest shareholder, and the company's chief executive, Lyndon Rive, is Musk's cousin.
Some are questioning why Tesla had to buy SolarCity rather than just work closely with it. SolarCity has struggled lately, and so some are calling this a Tesla-financed bailout.
John McAreavey, whose wife Michaela was murdered on honeymoon in Mauritius six years ago, has returned to the island.
[NEXT_CONCEPT]
US electric carmaker Tesla has offered to buy solar panel company SolarCity in a bid to expand its clean energy business.