We compared every aspect of Carnival's US and UK cruise ships. Here's what it's like to sail on each.

In July, Monica Humphries joined 2,700 vaccinated passengers on the Carnival Vista, the first Carnival ship out of the US since the pandemic. The ship embarked from Galveston, Texas, and made stops in Mahogany Bay, Honduras; Belize; and Cozumel, Mexico. Approximately 95% of passengers on Monica's cruise were required to be fully vaccinated before boarding.

Mikhaila Friel boarded Cunard's Queen Elizabeth ship in October for a five-night Western Europe voyage which embarked and disembarked from Southampton, England, and stopped in Amsterdam, the Netherlands, for two nights. She was one of 1,248 passengers on board, and all passengers were required to be fully vaccinated before fully boarding.

(For full disclosure, Insider paid for both cruises, per our reporting standards.)

While both Cunard and Carnival Cruise Lines are owned and operated by Carnival Corporation, each line attracts vacationers looking for different experiences.

Founded in 1972 by business mogul Ted Arison, Carnival Cruise Lines is known for its "fun ships," which operate budget-friendly cruises with various entertainment, according to Cruise Critic.

Cunard was founded over a century earlier in 1840. In 1998, Carnival Corporation took over and purchased it, and Cunard has since earned the reputation as one of Britain's most formal and luxurious cruise lines. Most recently, it won the Best Luxury Cruise Line award at the British Travel Awards 2019.

Throughout the entire cruise, Mikhaila spotted details — like ballroom-dancing classes and jazz band performances — that helped the Cunard line establish itself as a luxury vacation.

Meanwhile, the details Monica noticed, which included casinos and casual formal nights, fit right into Carnival Cruises' reputation as a "fun ship."

Here's a closer look at how the two ships differed.

Monica's seven-day cruise cost $1,081, or about £788, without gratuities. Mikhaila's cruise cost £628, or around $856 without gratuities.

The nightly rate on the Carnival Vista was about $20 cheaper than the Queen Elizabeth.

The Carnival Vista ship can hold up to 3,934 passengers compared to the Queen Elizabeth's 2,081 guest capacity. The Carnival Vista is 1,000 feet long and 133,500 tons with 15 decks and 1,450 employees.

Meanwhile, the Queen Elizabeth ship is slightly smaller in length at 965 feet, has 980 crew members, and 12 decks. The ship weighs around 90,900 tons, according to Travel Weekly.

Monica noted that everyone on the Carnival Vista was celebrating the moment they stepped onto the ship. She spotted people sipping pina coladas and strawberry daiquiris at the bar, and loud music echoed through the lobby.

Meanwhile, Queen Elizabeth guests were welcomed by musicians who played relaxing music, Mikhaila reported. Passengers were scattered across the ship, with some indulging in afternoon tea and others lounging on deck chairs.

For formal night, Monica dressed in a casual black jumper and strappy sandals. While she wasn't overdressed, she also wasn't underdressed. Throughout the night, she spotted a handful of passengers in gowns, but the vast majority of people wore shorts and casual dresses.

Meanwhile, there were two formal nights on Mikhaila's cruise, both of which were themed. Mikhaila dressed to both themes (black-and-white theme and roaring '20s theme, pictured above). Although guests were not required to dress to the theme, they were asked to dress in formal wear when dining in the main restaurant.

Guests on the Carnival Vista could choose between 13 eateries including buffets, sit-down restaurants, taco stands, and burger joints. Some of the restaurants were free and others came with an added cost, but there was clearly an abundance of options.

Meanwhile, guests on the Queen Elizabeth could choose from the Britannia restaurant or the Lido buffet for their meals and snacks. There were also three other formal restaurants, which were exclusive to guests staying in the luxury penthouse suites.

Each night, Monica and Mikhaila joined hundreds of passengers for dinner in their ship's main dining room. The menus, which offered guests an appetizer, main entrée, and dessert, were served by cruise workers in smart attire.

The Carnival Vista embraced American cuisine. The ship had everything from Guy Fieri's Pig and Anchor Bar-B-Que Smokehouse to Guy's Burger Joint to a pub and brewery. With so many options, Monica was bound to find something she liked. But by the end of the trip, a taco stand serving bean tacos and taco salads became her favorite spot.

Meanwhile, Mikhaila enjoyed Cunard's afternoon tea in the Lido buffet, which involved a selection of cakes and scones. While Mikhaila noticed there wasn't as wide a variety of food as on Monica's cruise, she thought the quality of food was excellent.

Both buffets on the Cunard and Carnival ships offered a range of items, from pasta, pizza, to cakes.

The Carnival Vista had simple decor that showcased Carnival branding. During the cruise, which took place on the Fourth of July, staff added extra decorations like ribbons, banners, and streamers.

But the decor couldn't compare to the chandeliers and luxury details found throughout the Queen Elizabeth. The ship's decor also hinted at its connection to royalty, with several portraits of the Queen and Prince Philip.

The cruise line has been linked to the British royal family since 1934 when it named a ship after Queen Mary, according to its website.

Ballroom dancing appeared to be one of the more popular activities during Mikhaila's time on the Queen Elizabeth, but there was also a nightclub that played more modern music.

There were some refined activities on the Carnival Vista. A band played at the Havana Bar and an art auction took place a few times on the seven-day journey. But the activities Monica noticed to be the most crowded embraced louder music, singing, and dancing. For example, karaoke was a hit and crowds flocked to the cruise deck every night for a dance party.

The entertainment on the Carnival Vista embraced a fun, carefree attitude. Monica attended shows where audience members were urged to sing and dance to performances of rock-and-roll songs. And nearly every night, she noticed that the comedy bar was packed with people laughing at the adults-only show.

Meanwhile, on the Queen Elizabeth, guests were able to try ballroom dancing, and were also treated to a performance from a professional dancing duo. Mikhaila also noticed professional violinists playing in the lobby each night.

Water was a main attraction on the Carnival Vista. The ship had three pools, six hot tubs, and an entire waterpark. Nearly every chair and lounger near the pool would be filled each afternoon, and Monica noticed the pool was often crowded with swimmers.

The Queen Elizabeth had an outdoor pool and a hot tub, however, Mikhaila noticed that the chilly October weather meant there weren't as many people enjoying it.

Both reporters stayed inside the cheapest rooms available on their respective ships.

The interior stateroom on Cunard's Queen Elizabeth, which cost slightly more, was advertised online as 152 square feet, while the room on the Carnival Vista was a bit larger at 185 square feet.

The rooms seemed similar and both had a King-size bed, bathroom, and closet

When Mikhaila arrived in her room, she had a bottle of wine and a coffee station waiting for her, which is standard for Cunard cruises. Monica did not.

With vastly different destinations — Amsterdam versus Cozumel, Belize, and Honduras — the activities that were offered to passengers were also contrasting.

During the seven-day cruise, Monica went scuba diving for $92 and on a snorkeling and kayaking excursion that cost $47. Mikhaila embarked on a walking tour and canal cruise, which cost $72.

While both reporters traveled on large ships, Monica disembarked the Carnival Vista with a sunburn and memories of swimming in the Caribbean.

Meanwhile, Mikhaila packed up her floor-length dresses and disembarked full of treats from afternoon tea.

While the cruises may be owned by the same corporation, the atmosphere created on each ship couldn't be more different — and that's probably for the best.

Sailing is subjective, with passengers from around the world choosing the experience for an abundance of reasons. Having drastically different cruise lines to choose from will help ensure travelers choose the right cruise line, and ship, for their interests.