There is nothing subtle about the world’s largest cruise ship.

Royal Caribbean’s new, nearly 1,200-foot-long and 250,800 gross ton Icon of the Seas - which set sail from the Port of Miami on its maiden cruise just before sunset on Saturday - towers like a multilayered birthday cake.

The frosting on top is in the form of seven swimming pools, a whimsical striped carousel, groves of tropical greenery and twisting waterslides in green, pink, blue and orange.

When the $2 billion ship sailed into Miami with music blasting on January 10, after crossing the Atlantic - with a pitstop on Puerto Rico - from the shipyard in Turku, Finland, where it was built, it was greeted with a cacophony of fireboat salutes and a banner flag flyover. The commotion brought traffic to a halt along the causeway to Miami Beach that parallels the cruise ship channel.

Argentine soccer star Lionel Messi was even in on the ship’s early fanfare as the Icon of the Seas’ “godfather,” christening the 20-deck ship on January 23.

The ship is officially the biggest cruise ship in the world, with Royal Caribbean’s Wonder of the Seas, new in early 2022, trailing close behind at 1,188 feet long and 235,600 gross tons.

Passengers on its maiden voyage, a sold-out, seven-night cruise to the Eastern Caribbean, will be able to enjoy some next-level experiences at sea.

Icon of the Seas’ list of superlatives and firsts is long

Finding time to fit in everything onboard Icon of the Seas promises to keep passengers busy. And speaking of passengers, the ship can carry a whopping 7,600 guests at full capacity, along with 2,350 crew – so about the whole population of Sedona, Arizona.

Among the behemoth’s attractions, there’s Category 6 – the ship’s 17,000-square-foot water park, currently the largest at sea and sprawled across Decks 16 and 17, with six slides that include Frightening Bolt (the tallest drop slide at sea at 46 feet or 14 meters) and the first family raft slides at sea (Hurricane Hunter and Storm Surge).

The ship has the first cantilevered infinity pool at sea, as well as the largest swimming pool at sea (the 40,000-gallon Royal Bay) and the largest ice arena at sea (Absolute Zero, where guests can skate or watch a performance).

Some 50 musicians and comedians keep passengers entertained with ensembles that include the largest orchestra at sea (16 pieces) as well as the first at-sea performance of “The Wizard of Oz,” complete with flying monkeys. There’s even a resident golden retriever, Rover, dubbed the Chief Dog Officer, who is still a puppy and appears on her own schedule alongside a dedicated handler.

The buzz is real – and so is the blowback

Long before it arrived in Miami, social media images of Icon of the Seas generated online buzz from eager vacationers as well as heavily polarized opinions about the over-the-top ship, in particular about the potential environmental impact of such a large ship.

A Royal Caribbean spokesperson said Icon of the Seas is 24% more energy efficient than required for ships designed today. The company plans to introduce a net-zero ship by 2035.

The ship is Royal Caribbean’s first to be powered by liquefied natural gas (LNG). Not everyone is impressed with that choice.

“Royal Caribbean’s decision to use LNG is their biggest climate blunder,” said Bryan Comer, marine program director at The International Council on Clean Transportation.

“LNG is mostly methane, a greenhouse gas that traps more than 80 times more heat than carbon dioxide in the first 20 years after its emitted. The Icon of the Seas uses engines that release methane to the atmosphere in the form of ‘methane slip.’”

The organization says LNG can only “significantly contribute to achieving climate goals” when methane-slip and other factors are greatly reduced or eliminated, which the council says is still a major challenge.

The ship’s parabolic bow — a first for Royal Caribbean — is designed to help a ship move more easily through the water and does help reduce fuel consumption and emissions, Comer said, adding that it also helps the cruise line’s bottom line.

The ship produces more than 93% of its fresh water through reverse osmosis. And Icon of the Seas also has the brand’s first microwave-assisted pyrolysis waste-to-energy system (MAP), used to convert onboard waste to gas that the ship can use as energy.

High interest from avid cruisers

Interest in the massive ship is undeniably high among cruise devotees.

Colleen McDaniel, editor-in-chief of Cruise Critic, told CNN Travel that Icon of the Seas is the most researched topic on the cruising website so far in 2024.

For avid cruisers, McDaniels said, the biggest buzz around Icon of the Seas is the fact that it’s the first in an entirely new class of ship for Royal Caribbean, which last debuted a new class of ship, Quantum Class, in 2014.

“Thinking about all that’s changed in cruise – and travel – in the past 10 years, there are so many new concepts and options to be excited about onboard,” McDaniels said, calling Icon of the Seas “absolutely groundbreaking for the industry.”

Next up in Royal Caribbean’s Icon Class of ships is Star of the Seas, under construction in Finland and due to debut in August 2025 for Caribbean sailings out of Florida’s Port Canaveral, near Orlando, with similar amenities to Icon of the Seas.

“The unprecedented demand for Icon of the Seas prompted Royal Caribbean to open bookings for Star of the Seas – Icon’s sister ship – three months earlier than originally planned,” said a company spokesperson.

New ship ‘neighborhoods’

Icon of the Seas’ eight different onboard “neighborhoods” are designed to appeal to cruising’s multigenerational demographics as well as passengers with different interests, including families with young kids and adults-only travelers.

Offerings within them range from Royal Caribbean’s first swim-up bar at sea, Swim & Tonic, in the ship’s Chill Island neighborhood, to The Lemon Post in a new family-focused neighborhood called Surfside, where guests can order mommy-and-me and daddy-and-me cocktails and mocktails within steps of a kiddie splash area.

While Royal Caribbean was already known for its onboard neighborhoods, which guests can bounce between, McDaniels said Icon of the Seas has leveled up the concept on this ship.

“Without a doubt, this ship was created to compete directly with resorts on land, particularly those that cater to families,” she said.

The new ship’s most anticipated offering for families might be Surfside on Deck 7. Geared toward families with kids 6 and younger, it centers around a Seussian-looking carousel for which kids made the ultimate call on the ride-on characters (a rainbow-toothed narwhal and a pool floatie-style flamingo, among other whimsical creatures).

The carousel sits steps from several family-friendly dining options, including a buffet, snack window and new specialty restaurant, Pier 7, with all-day brunch and where kids younger than 12 eat free. And two water play areas for young kids are also nearby and right next to the Water’s Edge pool, where parents can ostensibly keep an eye on their children while also relaxing with ocean views.

For the 18 and up crowd, another new onboard neighborhood, The Hideaway, takes its inspiration from international beach club scenes, with a multilevel terrace with uninterrupted ocean views and the first suspended infinity pool at sea, cantilevered 135 feet (41 meters) above the ocean.

The ship’s features will be particularly impressive to people who have never cruised before, said Rob Clabbers, founder and president of Q Cruise + Travel, a Virtuoso agency in Chicago.

“For Icon of the Seas, the clients that are most excited are families with younger children,” said Clabbers, pointing to features such as the water park, pools and a surf simulator.

The ship is also generating interest from clients who aren’t necessarily traveling with kids, he said, especially the Suite neighborhood, which is an area that feels like a ship-within-a-ship reserved for suite guests only. Royal Caribbean’s largest Suite neighborhood to date, it spans four decks and has its own private sun deck, pool and hot tub as well as two exclusive restaurants.

“The entertainment, the amenities, the restaurants, the quality of shows and variety of activities – and even the design of the interior and exterior spaces – is simply mind boggling for those who are used to staying in most land-based resorts,” Clabbers said. “And that doesn’t even include the things you can do while ashore.”

More than 40 onboard restaurants, bars and lounges include 21 options new to Icon of the Seas, among them pay-extra offerings such as a walk-up sushi window at Izumi, specialty restaurant Empire Supper Club (with Wagyu ribeye and butter-poached langoustine on an eight-course menu that costs $200 per person) and a walk-up Champagne window at Bubbles in the ship’s Central Park area.

The 28 different kinds of onboard accommodations range from 157-square-foot interior plus cabins, which start at $3,600 per week for two people, to the three-story Ultimate Family Townhouse, with its own wraparound deck, cinema, outdoor hot tub and spiraling slide to ride between decks that averages $100,000 per week and can accommodate eight people.

A marvel of engineering and big aspirations

Impressive feats of engineering are on display everywhere on Icon of the Seas.

The 82-foot-tall steel and glass AquaDome crowns part of the top of the ship, housing a theater where high-divers perform, a 55-foot-tall water curtain feature, a bar and Royal Caribbean’s first food hall.

The sphere-shaped Pearl, on the ship’s World Promenade, towers three decks high and cycles through colorful vignettes, drawing selfie-takers while simultaneously providing structural support midship and opening the area to expansive ocean views.

At a recent press panel onboard the ship, Michael Bayley, president and CEO of Royal Caribbean International, told media that the ship “ticks all the boxes” for what the company was hoping to create.

“It’s big, it’s bold, it’s perfect for the Caribbean, it’s perfect for our market,” Bayley said.

The ship’s offerings are in response to demands the brand heard from cruisers both new to cruising and already loyal to Royal Caribbean, said Jay Schneider, Royal Caribbean’s chief product innovation officer.

“We researched and concept tested and heard the same thing,” he said, naming the desires to make memories, try “firsts” together, bond and have options galore that include “a mashup of thrill and chill” as commonalities that resonated over and over in research sessions.

“Nowhere in our office is there a thing that says, ‘Let’s go build the world’s biggest ship,’” Schneider told CNN Travel. (The original plans were for a ship that was about 50,000 gross tons lighter).

Royal Caribbean International is clearly pitching Icon of the Seas to a market that goes beyond cruising.

“We didn’t create Icon to compete with other cruise ships,” he said. “We designed it to compete with any other family vacation you wanted to do anywhere else on the planet — from skiing to Vegas to the Grand Canyon.”