Stepping foot on the Icon of the Seas – the world’s newest and biggest cruise ship – feels like entering another world.

The floating city is 365 metres-long (1,200ft), weighs 250,800 gross ton and, at capacity, will carry 7,600 people to Caribbean islands on seven-night voyages, with prices starting from $1,775 (£1,398).

I’ve joined 4,000 people for a three-night taster tour before the vessel embarks on its first revenue voyage later in the week.

There is a buzz around the ship, a sense of childish excitement from people donning Icon merchandise. “I had to be here,” I hear more than once in the first evening onboard, “I couldn’t miss this.”

On the first evening, hundreds of guests fill the ship’s AquaDome for the Icon of the Seas’ official naming ceremony where Royal Caribbean Group president and CEO Jason Liberty introduces footballer Lionel Messi to trigger the traditional breaking of the champagne bottle on the ship’s bow.

Jason says: “Icon of the Seas is the culmination of more than 50 years of dreaming, innovating and living our mission to deliver the world’s best vacation experiences responsibly.

“She is the ultimate multigenerational family vacation, forever changing the status quo in family travel and fulfilling vacation dreams for all ages on board.”

He’s right – while the ship will sail to islands like Saint Kitts and Nevis, it is the Icon itself that is the star destination.

Life onboard the world’s biggest cruise ship

There are eight ‘neighbourhoods’ – each a space with their own unique vibe, decor and entertainment. Aimed at families with younger children aged six and under, Surfside is lit up like a neon candy land with water attractions including a pool and a ‘baby bay’, a carousel, and an arcade.

Central Park is an open-air oasis in the middle of the ship where the deck is bordered with living plant walls. Weaving along the path lined by greenery you’ll find specialty restaurants such as Izumi, a Japanese eatery where you can enjoy sushi and hibachi, and a walk-up champagne bar called Bubbles. You can sample these luxury spots for an added price.

A standout feature on the ship is Crown’s Edge, located on Thrill Island, a neighbourhood with six record-breaking waterslides. Crown’s Edge is a skywalk that will give vacationers an adrenaline-pumping experience as it culminates in a zipline that hangs 47 metres over the ocean.

Credits: PA; Author: PA;

The evening shows are just as dazzling and the company seems focused on hitting ‘firsts’ – you can watch The Wizard of Oz in the Royal Theater, the first rendition of the classic at sea, or you can take a seat at Absolute Zero, the largest ice arena at sea. The aqua show at the new AquaDome boasts state of the art technology, including four robotic arms to pull off a spectacular performance with high divers and synchronised swimmers.

Despite the 4,000 people onboard, I never find myself struggling for a place to soak up the sun or cool down in the shade. There’s plenty of space to eat in the three-storey dining room and at food market Windjammer, both places offering complimentary food and drinks.

One downside I can envisage is overcrowding when the ship reaches its capacity of 7,600 guests but Royal Caribbean seem to have a handle on the flow of people throughout the boat. All bases seem to be covered for the different demographics onboard, with families flocking to Surfside, and the karaoke and piano bars staying open until the early hours.

Relaxing on Perfect Day at CocoCay

As part of my short voyage, we visit 125-acre Perfect Day at CocoCay, one of the Berry Islands – a collection of Bahamian cays that was first leased by the Royal Caribbean Cruises Ltd in 1988.

Disembarking at the port in CocoCay, Bahamas, I turn to glance back at the vessel parked next to another Royal Caribbean cruise ship – Vision of the Seas. With 20 decks, the Icon of the Seas stands like a behemoth next to the smaller ship.

The island has undergone extensive renovations with its $250m overhaul adding a waterpark with 14 waterslides and the Hideaway, an adults-only space with a private beach, pools, cabanas and live music.

While much of CocoCay feels like a theme park, my favourite spot is Chill Island, a quieter part of the cay where you can laze on a lounger or take a dip in the crystal-clear water, accompanied by schools of fish.

Credits: PA; Author: PA;

What impact does the ship have on the environment?

There’s no doubt the Icon is impressive but how ethical a ship of this size and how much damage is it doing to our environment?

Royal Caribbean say they are taking steps to improve the efficiency of their ships, with Icon having a waste-to-energy system using Microwave Assisted Pyrolysis technology to turn trash into energy on board.

Icon has a dedicated environmental officer to test the water onboard daily and oversee the ship’s environmental initiatives and training.

The ship is powered by six dual-fuel engines that have the ability to use liquefied natural gas, which environmentalists have criticised as being a risk for leaking methane into the atmosphere.

But according to Royal Caribbean, Icon of the Seas is 24% more efficient than the required standards for modern ships and its parent company, Royal Caribbean Group, plan to have a net-zero ship by 2035.