Because cruise vacations are easy to plan and relaxing, it's no wonder about 31.5 million people took them in 2023, according to data from Statista. 

Ranging from inconvenient to catastrophic, a tiny portion of these vacationers had their plans altered by unforeseen circumstances in 2023:

Cruises turn into ‘nightmares’ after marine life prevents entry into New Zealand

Pesky algae, barnacles, oysters and even snails prevented ships from entering New Zealand's waters three times last winter, leaving a cruise line's human passengers with significant changes to their plans. 

THIRD AUSTRALIAN CRUISE IN WEEKS TURNS INTO 'NIGHTMARE' AFTER FUNGUS OUTBREAK PREVENTS ENTRY INTO NEW ZEALAND

The Seven Seas Explorer of Australia's Regent Seven Seas Cruises fleet was forced to wait in open water for a cleaning crew to mitigate what New Zealand officials described as "higher than allowed levels of algae, barnacles, tube worms and potential oysters" clinging to ships, according to RNZ. 

After departing from Sydney Dec. 29, 2022, passengers expected to stop at eight ports and three fjords with just three days at sea. But an American passenger on the ship told Fox News Digital passengers instead spent 11 days at sea, only visiting one port.  

Seven Seas Explorer

The Marshall Islands flagged cruise ship "Seven Seas Explorer" anchors in Alanya, Antalya, Turkey Sept. 4, 2022. (Mert Canturk/Anadolu Agency via Getty Images)

New Zealand officials blocked two additional ships from entering their waters due to excessive marine life on their hulls last winter. Viking Cruises ship Viking Orion was left stranded at sea for eight days in January for what the company told Fox News Digital was a "limited amount of standard marine growth." More than 900 passengers on that cruise were refunded for their trips, according to earlier reporting by Fox News Digital. 

In late December 2022, a Princess Cruise Lines ship was held back by New Zealand officials for an excessive number of unexpected snail stowaways. Many passengers were dissatisfied with a $100 voucher and a voucher for 15% off future cruises they received along with an apology from the crew, per Reuters. 

Bahamas-bound passengers shocked after being rerouted to frigid locations

Passengers who had packed their shorts and sunglasses for a trip to the Bahamas were shocked after their ship was rerouted to Boston, Maine and Canada over "unreasonable" weather changes.

MSC Meraviglia passengers Lakeya Allen and Val Montgomery appeared on "Fox & Friends" and recalled their reaction to the unforeseen circumstances.

"They sent this itinerary a couple hours before we were getting ready to leave to board the plane," Allen said. "I have three children, and I would have to repack all three bags. And we actually have maybe six bags or so. So, it was just too much to change, and we just left." 

Initially, the ship was slated to make stops at Port Canaveral, Florida; Nassau, the Bahamas; and MSC's private Ocean Cay island.  

The company told Fox Business that "unseasonable and rapidly worsening weather ... would have made it impossible to safely reach the southern Atlantic Ocean from New York City," and the only other option would have been "to take the more extreme step of canceling the cruise — and thousands of people's vacations — outright."

CRUISE SHIP FIRE NEAR ALASKA PROMPTS DOZENS TO EVACUATE

Engine room fire prompts more than 50 passengers to evacuate Alaska cruise ship

All 51 passengers and 16 staff members were forced to suddenly abandon their sightseeing cruise through Alaska's Glacier Bay National Park when a fire started onboard in June.

UnCruise Adventures said the fire originated in the engine room and that all the affected passengers would be compensated. 

After evacuating the Wilderness Discoverer, the passengers were reportedly placed on another cruise in the area. 

Eleven crew members remained onboard the ship as it was towed to Ketchikan, the company said. 

Cruise ship near Alaska

A cruise ship near Alaska Jan. 1, 2012.  (Wolfgang Kaehler/LightRocket via Getty Images)

Rough seas sent tables flying, left passengers ‘fearing for their lives’

Around 100 people were injured in November when their cruise ship entered rough seas off the coast of France. 

Treacherous conditions caused the Saga Cruises' Spirit of Discovery ship's automatic safety systems to activate. This made the vessel suddenly shift to one side before bringing it to a stop. 

VIDEO SHOWS HORRIFYING MOMENTS CRUISE SHIP PASSENGERS 'FEARED FOR THEIR LIVES': 'TABLES WERE FLYING'

Five people were transported to hospitals when the ship docked in Portsmouth, a Saga Cruises spokesperson said of the Nov. 4 incident. 

A thousand passengers aboard the ship were scheduled for a 14-day trip to the Canary Islands, but staff decided to prematurely head back to the United Kingdom after the unsettling incident. 

One passenger told the BBC the situation was dire. Another said people "feared for their lives."

"To say 'minor injuries' is an insult to the many horrific broken bones, pelvises, lacerations, stitches etc. that were caused [to] a very old passenger clientele," the passenger said of the official reaction from Saga Cruises. "People were writing texts to their loved ones in case we capsized."

Rogue wave blows out Norwegian cruise ship's ability to navigate

The MS Maud lost power after it was hit by a huge wave last Thursday as the ship was sailing toward Tilbury, England, from Florø, Norway. 

CRUISE SHIP FALL LEFT VIRGINIA WOMAN FEARING 'SHE WAS GOING TO DIE' IN FOREIGN HOSPITAL, DAUGHTER SAYS

Although none of its 266 passengers or 131 crew members were injured, crew members were forced to manually pilot the ship back to port with emergency propulsion systems, company HX told NBC News. 

The wave reportedly shattered windows on the ship's bridge, causing water to enter the vessel and short out electrical components, per Reuters. 

One passenger's Facebook video showed the view from her window on the vessel, in which the cruise ship creaked and bobbed amid the high waves. 

Two civilian support vessels aided the ship back to port in Bremerhaven, Germany,  the Danish Joint Rescue Coordination Center said in a statement Friday. 

Denise Hammond, 64

Denise Hammond, 64, is pictured at a stop on her Carnival cruise before falling and fracturing her hip and elbow Oct. 4. (Provided by Rachel Matthews)

American feared she would die in a foreign hospital after breaking hip on cruise ship

Denise Hammond, 64, fractured her hip and elbow in a fall on the Carnival Cruise Luminosa Oct. 4. 

After doctors on the vessel took X-rays of the woman and determined she would need additional care, she was left to wait as the ship made its way to its next stop. Four days later, Hammond was brought to Siloam Hospital in Manado, Indonesia. 

There, her daughter told Fox News Digital, "the hospital conditions were really atrocious," and doctors told Hammond they didn't have the proper equipment to treat her fractured bones. 

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"They weren't doing any scans or blood tests, giving any kind of anticoagulants. ... We were concerned she was going to die in that hospital," Rachel Matthews said of her mother's ordeal. 

After receiving money via GoFundMe and working tirelessly with the U.S. embassy, the family finally hired a transport company to take Hammond to the nearest hospital that could properly treat her, located in Bangkok, Thailand. 

According to the family's GoFundMe, Hammond's surgeries there were a success. However, because of the nine days she was left untreated, Matthews told Fox News Digital she needed "much more intensive surgery" because her injuries were "healing back incorrectly."