A leisurely trip by boat is relaxing for many people, especially if it’s on a cruise ship. The pandemic shut down cruise lines for over a year, but they’re finally reopening. Vaccinated guests can already travel again with several cruise lines.

Travel Weekly reports that many Carnival, Crystal Cruises, Norwegian Cruise Line, and Royal Caribbean ships set sail throughout July and August. Oceania, Regent Seven Seas, and two Disney Cruise ships soon followed. Although this is good news for travelers, experts worry about cruise ships’ negative impact on the environment.

The worst cruise ships for the environment

Friends of the Environment (FOE) gives all major cruise ships and cruise lines a grade based on their environmental effects. The ship’s air pollution reduction, sewage treatment, and water quality determine its grade. FOE also takes the company’s transparency in willingness to comply with these requirements into account. Any criminal violations related to these environmental policies factor into the final grade.

For the past four years, Costa cruise ships have committed the most criminal violations, FOE’s report cards show. All Costa ships also typically receive low grades for air pollution and sewage treatment. The Costa Fortuna and the Pacifica received the lowest scores in each category.

Also, Carnival has multiple ships that receive failing grades across the board, including the Liberty and the Pride. FOE also knocked down the company’s grade for criminal environmental violations.

Six other lines committed criminal violations. They are Royal Caribbean, P&O Cruises, Holland America, Princess, Seabourn Cruises, and AIDA. 

Although AIDA Cruises ships usually get better overall ratings, the AIDAcara and AIDAmira release tons of pollution. The Celebrity Constellation gets a marginal score for sewage disposal but fails in every other category. The same is true for multiple Norwegian Cruise Line ships.

In addition, both the Aurora and the Azura from P&O Cruises have the lowest ratings in each category. A few Oceania and Princess ships have relatively good air pollution prevention measures, but they fail for sewage treatment. Regent Seven Seas ships are usually the best with water quality but fall short in the other categories.

What are the most environmentally friendly cruise ships?

The only cruise ship to score an excellent overall rating was the Disney Wonder. It earned an average score for sewage treatment but high marks in all other categories. The same applies to Disney’s Fantasy and Dream ships, though the Magic received only an acceptable grade for air pollution reduction.

Princess Cruises’ Diamond Princess and P&O Cruises’ Pacific Adventure ships also have high grades overall, especially in water quality compliance. The Norwegian Star and Carnival Spirit have more acceptable grades than other ships from those companies.

Even ships with average grades overall still got failing scores in some categories. Most Norwegian and Princess ships received a D in water compliance, and many companies didn’t disclose this information. Two Regent Seven Seas ships got the lowest scores for air pollution.

Why do some ships produce so much pollution?

According to the Friends of the Environment, the EPA has said the average cruise ship produces 150,000 pounds of sewage each week. Some ships hold the sewage or use advanced waste removal systems, while others release literal tons of bacteria into the ocean. Additionally, one cruise ship can release more harmful gases each day than millions of automobiles.

In addition to obvious climate change concerns, the gases can adversely affect human health after prolonged exposure. If you plan to cruise anytime soon, consider sailing with Disney instead of Carnival or Costa.