Why Cruise Lines Keep Building the Same Ship Again and Again

Designing a new cruise ship is enormously expensive, complicated – and risky.

Once a cruise line and shipyard have developed a successful design, it usually makes far more sense to build several versions of it than to start again from scratch.

These groups are known as ship classes, and the vessels within them are usually called “sister” ships.

Repeating a design can reduce risk, make construction more efficient and give a cruise line several ships that deliver an experience recognisable to their loyal guests.

However, later ships are rarely exact copies. Cruise lines often use each new sister to sort out problems, add cabins, introduce attractions or respond to changing passenger wants and needs.

There are many times I have boarded a cruise ship and thought “this all seems very familiar, but I haven’t sailed on this ship before”.

The theatre is in the same place, the cabins look familiar, and I already know which staircase leads to the buffet.

This isn’t a coincidence. Cruise lines often build several ships from the same basic design.

Some classes contain only two ships, while others continue for years and include many vessels.

This is not simply a lack of imagination. There are strong financial, practical and operational reasons for doing it.

The later ships are not always identical and may actually be better – or worse – than the original ship.

What Does an “Identical” Sister Ship Actually Mean?

“Identical” refers to cruise ships built from the same basic design that form a class of ship. Internal decor will be different, so often the ships feel similar, but not the same.

The ships within that class are known as “sister ships”.

They will usually share:

• The same basic hull.
• A similar length, width and passenger capacity.
• Almost identical deck layouts.
• Similar cabin arrangements.
• The same engines.
• Many of the same restaurants and public spaces.

They may look identical from a distance while having noticeably different interiors.

People use the term “identical” for these sister ships, but in reality most sister ships have at least a few differences.

An example of this would be Celebrity’s Solstice class ships.

Celebrity Solstice was the first ship in the class, followed by Equinox, Eclipse and Silhouette.

The last ship in the class, Reflection, is slightly larger than the earlier ships. An extra deck was added, along with 72 extra cabins and expanded luxury suite areas.

This was the last Reflection-class ship, and no more were built. They then moved on to the Edge-Class ships, with the innovative Celebrity Edge being launched in 2018.

Designing the First Ship Is the Hardest Part

The first ship in a class is often described as the “prototype”.

Before construction begins, the cruise line and shipyard must develop:

• The hull and superstructure.
• The engine and propulsion arrangements.
• Safety systems.
• Crew and passenger flows.
• Cabin modules.
• Kitchens, storage and waste systems.
• Restaurants, theatres and entertainment spaces.

The design also has to comply with maritime rules and be practical for thousands of passengers and crew.

Building the first ship means testing a design that has never operated before.

Once the design has been created and approved, much of that work can be reused on the sister ships.

Repeating an established class of ship avoids having to begin the entire design process again.

Building a Series Is More Efficient for the Shipyard

Modern cruise shipyards are set up to build ships in a production sequence.

Workers, subcontractors and suppliers become familiar with the design they are working on.

Problems discovered while constructing the first ship can be anticipated – and avoided – on the next one.

The shipyard can reuse plans, processes, tooling and manufacturing equipment.

Cabins are often constructed as modules elsewhere before being slid into the side of the cruise ship and installed.

You can see that happening here:

Repeating cabin types and technical spaces can make production easier and more predictable.

Cruise Lines Can Spread the Risk

A new ship design is effectively an enormous experiment.

Cruise lines do not know for certain how passengers will react to the new design until the first ship enters service.

Ordering several ships based on one proven successful design is less risky than creating a completely different prototype every few years.

Once the first ship proves popular, additional sisters can be ordered with greater confidence.

A successful ship class can quickly become the backbone of a cruise line’s fleet.

Successful Ships Produce Better Financial Returns

Cruise lines are businesses, so a design that earns strong returns is likely to be repeated.

The company already understands:

• How many passengers the ship can carry.
• Which cabin categories sell well.
• How much onboard revenue the venues will generate.
• How expensive the ship is to operate.
• Which itineraries will suit it.

Building another version of a profitable ship is less speculative than launching an entirely new concept.

Carnival Corporation selected Excel-class ships for many additional sister ships because they were producing some of the highest returns.

The first Excel-Class ship launched was AIDAnova in 2018. Many other ships followed, sailing for other Carnival brands.

Excel-Class Ships:

Carnival Cruise Line – Mardi Gras (2021), Carnival Celebration (2022), Carnival Jubilee (2023) are now sailing. Carnival Festivale and Carnival Tropicale are being built.

P&O Cruises – Iona (2020) and Arvia (2022)

Costa Cruises – Costa Smeralda (2019), Costa Toscana (2021)

AIDA Cruises – AIDAnova (2018), AIDAcosma (2021)

To put it in simple terms, when a ship design works commercially, cruise lines want more of them.

It Makes Operating the Fleet Easier

Having similar ships can simplify some parts of running a large cruise ship fleet:

• Crew members can move between sister ships and still find their way around the familiar layouts.
• Maintenance teams may work with similar equipment and systems across the fleet.
• Cruise lines can use similar spare parts and supplier arrangements for all of their ships
• Restaurant menus and operating procedures can be repeated from one ship to the next.
• Crew training can be adapted from existing ships, rather than created entirely from scratch.
• Marketing teams already understand the main selling points of the ship.
• Cabin photographs, deck-plan knowledge and customer advice can be reused more easily.

The concept of sister ships that evolve and change with time is nothing new.

Even RMS Titanic had two sister ships, the Olympic and the Britannic.

Britannic, the youngest sister, was built last, and its design changed during construction after the Titanic disaster.

It became wider for better stability, had a double hull, and included huge gantry davits to carry the extra lifeboats needed.

Passengers Know What to Expect

Familiarity can be reassuring to cruising guests. Someone who enjoyed one ship may deliberately book a sister ship to be sure that they will enjoy the cruise.

Returning passengers may already know the layout of the ship.

Cruise lines can build a recognisable experience across the fleet, without making every ship completely identical.

A clear advantage for the travelling public is that the newest ships tend to have the most expensive fares. You might be able to find a better deal on a slightly older ship in the same class.

Viking provides a good example of a company that orders the same ships over and over again.

Neptun Werft shipyard has built more than 60 structurally identical river ships for Viking River Cruises.

Viking’s ocean fleet, built by Fincantieri shipyards in Italy, has expanded around a highly consistent design.

Public spaces, restaurants, and lounges mirror one another so guests feel instantly at home on any Viking ocean vessel.

I love the design of Viking ocean ships. Have a look at the cruise I took on Viking Star here:

Sister Ships Allow Cruise Lines to Grow Quickly

A cruise line may want to add thousands of passenger berths over several years.

Developing a new type of ship every time would add more cost and time and involve some uncertainty.

Ordering a series gives the company a pipeline of successful ships arriving at regular intervals.

The ships can then be positioned in different regions. One may sail in the Caribbean while another serves Europe or Alaska.

This allows the cruise line to offer a similar product in several markets at once.

An example of this would be P&O’s Arvia and Iona. Arvia is known as the sunshine ship and was tweaked to make her suitable for hot climates.

Her Skydome has a retractable roof, whereas Iona’s does not. Arvia has an adult-only swim-up bar and an infinity pool geared toward sunbathing in hot weather. She regularly sails in the Caribbean during the winter months.

Norwegian Prima was introduced as the first of six planned new-generation ships for Norwegian Cruise Line.

After the Norwegian Prima and Norwegian Viva were built, the company moved on to the “Prima Plus” class ships.

Norwegian Aqua (launched 2025) was the first upgraded “Prima Plus” class ship, which was enlarged by about 10%.

Norwegian Luna (launched 2026) and Norwegian Aura (due 2027) are the next two Prima Plus class ships.

They ironed out issues on Prima and Viva. They reportedly alleviated bottleneck congestion and tight walkways reported on the earlier ships.

By sticking to the same basic design, Norwegian has been able to launch cruise ships very regularly.

Have a look at the first ship in the class, Norwegian Prima here:

Why Aren’t Sister Ships Completely Identical?

Cruise lines listen to passenger feedback on new cruise ships launched. They can then learn from issues reported on the earlier ships and try to rectify them.

Tweaks cruise lines may make:

• Popular venues may be enlarged.
• Unpopular spaces may be replaced with something that generates more income.
• Queuing, crowd flow or storage problems can be corrected.
• New cabin categories may be added, where necessary.

Emerald Cruises described its newest luxury yacht, Emerald Kaia, as a refinement of its earlier sisters based on guest feedback.

The ship retained a similar appearance but became slightly longer and carried more passengers than the earlier ships, Emerald Azzurra and Emerald Sakara.

Emerald Kaia features larger cabins; stateroom floor plans are roughly 10% larger.

There is expanded deck space. A Sky Deck and an enlarged spa featuring a salt therapy lounge and cold plunge pool.

They added new venues, a Night Market Grill and an internal Sky Lounge.

I was lucky enough to sail on Emerald Azzurra; I didn’t have any complaints about the original design!

Have a look at that amazing superyacht cruise here:

New Attractions

Cruise lines want a reason to market each sister as “new and improved”.

Later ships may receive different:

• Water slides.
• Restaurants.
• Bars.
• Shows.
• Children’s facilities.
• Suite areas.

The structure may remain similar, but the bits used by the passengers may change.

Norwegian Aqua features the Aqua Slidecoaster, the world’s first hybrid roller coaster and waterslide at sea.

Earlier ships had featured drop slides, duelling slides and GoKart tracks. The Aqua Slidecoaster is something completely new for Norwegian.

Watch me try out the Aqua Slidecoaster in the video below:

Increasing Passenger Capacity

Later ships may be stretched, widened or given an extra deck.

This creates what is sometimes called a “subclass” of ships.

An example of this would be Norwegian’s Breakaway Plus ships, developed from the earlier Breakaway design but they became larger and gained an additional passenger deck.

New Technology and Regulations

Several years may pass between the first and final ship in a class.

Safety rules, environmental requirements and available technology can change.

Later ships may gain different engines, shore-power equipment or energy-saving systems.

These changes can be significant to the cruise line, even when passengers barely notice them.

Why Do They Sometimes Build the Same Ship for Different Brands?

Cruise companies often own several different brands.

For instance, the largest cruise company, Carnival, also owns many other brands you will of heard of.

Some of these brands have been around for decades – or, in some cases, centuries- before being acquired by Carnival Corporation.

Sailing under the Carnival Corporation parent company, you will find:

• AIDA Cruises: A German-market cruise line known for its club-style casual resort ships. The company was originally established in the 1960’s; P&O bought a majority stake in 2000; P&O then merged with Carnival in 2003, and AIDA became a Carnival brand.
• Carnival Cruise Line: The company’s namesake, fun-focused, high-capacity mainstream line, established in 1972.
• Costa Cruises: An Italian-market brand featuring classic European styling. The cruising side of the business was established in 1986, but they have been owned by Carnival since 2000.
• Cunard Line: An old luxury British brand, established in 1840, famous for historic ocean liners and transatlantic crossings.
• Holland America Line: A premium mid-sized ship line with classic style, originally established in 1873 to take passengers between Rotterdam and North America.
• P&O Cruises: A major British brand catering primarily to UK travellers. Origins of P&O go back as far as 1837, but they were acquired by Carnival in 2003.
• Princess Cruises: A large premium-to-luxury line recognised worldwide. Originally established in 1965, they were later owned by P&O before merging with Carnival Corporation in 2003.
• Seabourn Cruise Line: An ultra-luxury, small-ship experience. Carnival became a shareholder of the company in 1991, but by 1998 had become the sole owner.

Some ships owned by Carnival Corporation may share an underlying hull and layout, even though the décor, restaurants and branding are completely different.

Using a shared hull or engineering platform can retain some of the benefits of sister-ship construction.

The company can then redesign the passenger areas to suit the different audiences.

This is why ships from different cruise lines can sometimes have surprisingly similar dimensions or layouts.

Ships sharing a class are not always officially described as “sisters”. Terms such as near-sister, modified sister or quasi-sister may be used instead.

A perfect example of this would be the Excel-Class Ships, operated by different cruise lines owned by Carnival Corporation. The ships below are all the same class of ship:

• Carnival Cruise Line: Mardi Gras, Carnival Celebration, Carnival Jubilee
• P&O Cruises: Iona, Arvia
• AIDA Cruises: AIDAnova, AIDAcosma
• Costa Cruises: Costa Smeralda, Costa Toscana

I sailed on P&O’s Arvia and Iona, then on Costa Smeralda.

It was quite hard to believe they were the same basic ship. Arvia and Iona have light, modern, understated interiors:

…where as Costa Smeralda has different bright colours on every deck – and public toilets decorated like beach huts!

Is the First Ship in a Class the Best One?

You can’t make the blanket statement that the first ship in the class is always the best.

The first ship may be better because:

• It may carry fewer passengers than later versions.
• It represents the original design.
• Some features may be removed from later ships.
• Prices may fall once it is no longer the newest vessel in the fleet.

Later sisters may be an improvement on the original because:

• Early design problems may have been tweaked and corrected.
• The ship may have newer technology than the older versions.
• Popular spaces that turned out to be too small may have been expanded.
• It may offer additional restaurants, cabins or attractions to entice passengers to book.

Newer does not automatically mean better. A later sister might have more cabins and carry more passengers, without getting any more public space. The ship could then end up feeling crowded.

Do Identical Ships Give Guests Less Choice?

There are certainly upsides and downsides to cruise lines taking this approach.

The Downsides

• Frequent cruisers may feel that ships within a fleet are becoming boring and repetitive.
• A cruise on one sister may feel very similar to another.
• Unique lounges, observation areas or promenade decks can disappear when a cruise line standardises its fleet.
• Cruise lines may become reluctant to take major creative risks once a class is successful.

The Benefits

• Passengers can confidently book another sister ship, knowing it will suit them.
• Familiar layouts make the first day easier.
• A cruiser may enjoy the same style of ship on a completely different itinerary. Sailing in the Caribbean and the Mediterranean can feel completely different, even if the ship is virtually the same.
• Older sisters can provide a very similar experience for less money.

When Does a Cruise Line Stop Building a Ship Class?

There are lots of reasons the cruise line might change their design of ship, including:

• Passenger expectations change over time and may want something different.
• The design may become harder to operate profitably if cruise lines have to lower fares to attract passengers.
• New environmental or safety rules may mean that the design of the ship no longer works for them.
• The cruise line wants to change to larger or smaller ships.
• New attractions such as dropslides and rollercoasters cannot fit into the old layout.
• The cruise line wants to reposition its brand, becoming more luxurious or more mainstream.

Then a newer class of ship will eventually replace the older one.

Ending building a certain class does not necessarily mean the ship’s design has failed. It may simply mean the design has reached the end of its natural life, and it is time to move on to something new.

Do I Prefer Sister Ships or Unique Designs?

Really, it depends on who I am sailing with, and what I want to get from the experience.

I sailed with my brother on P&O’s Iona, she was quite new and the first “Excel Class” ship we had sailed on.

We loved the size of the ship, all the different food venues, the Skydome, and the cabin design.

When I was looking for a cruise to take my nieces on, I knew that I could book the sister ship Arvia and know exactly what I would be getting. It was perfect for a multi-generational family holiday.

The following year, I took a short cruise on P&O’s smallest ship Aurora. She is an older cruise ship, with features like traditional teak decks, a tiered aft and a really lovely atmosphere onboard.

She didn’t have any of the impressive features found on the newer ships; the cabin interiors were dated – but she is a really interesting ship! I really enjoyed my time on her.

Cruising could get very boring if all ships end up basically the same, and I am always on the lookout for unusual or unique ships to try out.

The cruise ship that will always have a special place in my heart is Norwegian Spirit. I took my first ever cruise on her in 2005, and have sailed on her twice since then.

She is a completely unique ship in the Norwegian fleet, and Norwegian have spent millions on renovating her and bringing her up to modern cruise ship standards.

She was built way back in 1998 as SuperStar Leo for Star Cruises. Her sister ship, SuperStar Virgo, never sailed for Norwegian, but is still sailing for Star Cruises in Asia under the name Star Navigator.

Have a look at the amazing and unusual Norwegian Spirit here:

Before You Go

I recently sailed on a cruise ship that had been cut in half and made longer to increase passenger capacity. Find out all about that here:

I Cruised on a Cruise Ship That Was Cut in Half! Here’s Why

The ships in the P&O fleet aren’t all the same. Find out which one would suit you here:

Don’t Book The Wrong P&O Cruise Ship – I Tried 5 To Compare