Cruise ships can dump some waste into the ocean, but not the waste you think
Cruise ships are allowed to dump certain types of waste overboard—food scraps, biodegradable paper, and treated wastewater—but they are prohibited from dumping plastics, hazardous materials, oil, and most other garbage. The rules come from the International Convention for the Prevention of Pollution from Ships (MARPOL), a treaty that sets ocean dumping standards for all commercial vessels. The United States enforces these rules through the Act to Prevent Pollution from Ships, and violations can result in fines up to $25,000 per incident for cruise lines.
What makes cruise ship dumping complicated is that the rules change based on how far the ship is from shore. Within 3 nautical miles, almost nothing can be dumped. Between 3 and 12 nautical miles, a few categories become legal. Beyond 12 nautical miles, the rules loosen further. A cruise ship operating legally in international waters may be breaking the law the moment it enters U.S. territorial waters with the same waste still on board.
Key Takeaways
- Food waste and comminuted (ground-up) paper can be dumped more than 3 nautical miles from shore, but plastics and metals cannot be dumped anywhere.
- Treated wastewater can be discharged beyond 3 nautical miles if it meets specific treatment standards, but untreated sewage cannot be dumped in U.S. waters.
- Cruise ships must keep records of all waste disposal in an Oil Record Book and Garbage Record Book, which the Coast Guard can inspect at any port.
- Violations of dumping rules can result in civil penalties, criminal charges, and permanent damage to a cruise line's reputation and operating licenses.
- The distance from shore where dumping is legal varies by waste type, so a ship cannot straightforward dump everything once it leaves port.
What waste can legally be dumped and how far offshore it must happen
Food waste is the most commonly dumped material. Cruise ships can discharge food scraps and other galley waste more than 3 nautical miles from the nearest land, provided the waste is ground into particles no larger than 1 inch. This process is called comminution. The ship must also be moving at a reasonable speed so the waste disperses naturally rather than accumulating in one spot. A stationary ship anchored near a beach cannot dump food waste legally, even if it is technically 3 miles out.
Paper and cardboard products can be dumped under the same 3-nautical-mile rule, but only if they are comminuted or shredded. A cruise ship cannot straightforward throw a cardboard box overboard. Plastics of any kind—including plastic bags, bottles, fishing nets, and synthetic rope—are banned from ocean dumping everywhere, regardless of distance from shore. This is the rule most often violated, because plastic waste is generated constantly on a ship and temptation exists to dispose of it quickly.
Wastewater from sinks, showers, and laundries (called graywater) can be discharged beyond 3 nautical miles if the ship has an approved treatment system. Sewage (called blackwater) is more strictly regulated. In U.S. waters, including the Great Lakes and within 3 nautical miles of any U.S. coast, sewage must be treated through an approved marine sanitation device (MSD) or stored in a holding tank for later discharge at a port facility. Beyond 12 nautical miles from the nearest land, treated sewage can be discharged if the ship is moving and the treatment system meets international standards.
How the Coast Guard and international authorities monitor dumping
Every cruise ship operating in U.S. waters must maintain two record books: the Oil Record Book and the Garbage Record Book. The Garbage Record Book documents every instance of waste disposal—what was dumped, when, where, and how far from shore. The ship's officers sign and date each entry. These records are not private; the U.S. Coast Guard can board a cruise ship at any time and inspect these books. If the records show dumping in prohibited zones or dumping of prohibited materials, the Coast Guard can issue citations on the spot.
The Coast Guard also uses satellite monitoring and port state control inspections. When a cruise ship arrives at a U.S. port, Coast Guard inspectors board and verify that the ship's waste disposal records match its actual waste handling systems. They check whether the marine sanitation device is functioning, whether the holding tank capacity matches the ship's size, and whether the crew has received proper training on dumping regulations. A ship with falsified records or non-functional equipment can be detained until repairs are made.
International waters beyond U.S. jurisdiction are monitored by flag state authorities—the country where the ship is registered. A ship registered in the Bahamas, for example, is subject to Bahamian oversight, though the Bahamas has agreed to enforce MARPOL standards. In practice, enforcement in international waters is weaker than in U.S. territorial waters, which is why some violations occur far offshore where detection is less likely.
What happens when a cruise ship is caught dumping illegally
Civil penalties for illegal dumping start at $5,000 per violation and can reach $25,000 or more. A single incident of dumping plastic overboard counts as one violation, but if a ship is caught dumping on multiple dates, each date is a separate violation. A cruise line caught dumping repeatedly can face penalties in the hundreds of thousands of dollars. Beyond fines, the cruise line faces reputational damage, negative media coverage, and potential loss of port access.
Criminal charges are also possible. In 2016, Royal Caribbean pleaded guilty to dumping oil-contaminated waste and falsifying records; the company paid $18.5 million in penalties and agreed to enhanced environmental monitoring. In 2019, Disney Cruise Line paid $40 million to settle allegations of dumping oily waste and falsifying records over a period of years. These cases show that the Department of Justice treats cruise ship dumping as a serious crime, not a minor regulatory violation.
A cruise line convicted of dumping may lose its ability to obtain federal contracts, may be barred from certain ports, and may face restrictions on new ship construction or expansion. The reputational cost is often larger than the financial penalty. Passengers increasingly research a cruise line's environmental record before booking, and a dumping conviction can reduce bookings for years.
Why cruise ships generate so much waste in the first place
A large cruise ship carries 3,000 to 6,000 passengers and 1,000 to 2,000 crew members. Each person generates roughly 3.5 pounds of waste per day—food scraps, packaging, paper, textiles, and other materials. A ship with 5,000 people on board produces more than 17 tons of waste daily. Over a seven-day cruise, that is more than 100 tons. The ship cannot straightforward store all of this waste in a hold; space is limited, and waste decomposes and creates odor problems.
Modern cruise ships have waste management systems that separate garbage into categories: food waste, recyclables, hazardous waste, and general trash. Food waste is ground and can be legally discharged at sea. Recyclables are stored and offloaded at ports. Hazardous waste (batteries, fluorescent bulbs, cleaning chemicals) is stored in sealed containers and disposed of at certified facilities on shore. General trash is compacted and stored until the ship reaches port. The challenge is that even with these systems, the volume of waste is enormous, and the temptation to dump illegally rather than pay for shore-based disposal is real.
The difference between what is legal and what is safe for the ocean
Legal dumping and environmentally safe dumping are not the same thing. Food waste that is legally dumped at sea still affects marine ecosystems. When large amounts of organic material enter the water, it can create dead zones where oxygen levels drop so low that fish and other marine life cannot survive. A single cruise ship dumping food waste legally may not cause a dead zone, but hundreds of ships doing so in the same area can contribute to the problem.
Comminuted food waste also attracts scavenger fish and seabirds, which can alter local feeding patterns and population dynamics. Some environmental advocates argue that the 3-nautical-mile rule is outdated and that all food waste should be stored and disposed of on shore. The cruise industry counters that food waste is biodegradable and that the ocean has natural processes for breaking it down, especially in deep water far from shore.
Wastewater treatment on ships is also imperfect. A marine sanitation device removes solids and reduces bacteria, but it does not remove all pathogens, pharmaceuticals, or nutrients. When treated wastewater is discharged, it still carries some contaminants into the ocean. In areas with heavy cruise ship traffic—such as Alaska, the Caribbean, and the Mediterranean—the cumulative effect of treated wastewater from dozens of ships can affect water quality and marine life.
What cruise passengers can do to reduce waste on their ship
Individual passengers cannot stop a cruise ship from dumping legal waste, but they can reduce the amount of waste generated. Bring reusable water bottles and refill them at ship fountains rather than buying bottled water. Refuse single-use plastics like straws, plastic bags, and plastic cups. Eat smaller portions so less food is wasted. Use towels multiple times instead of requesting fresh ones daily. Participate in the ship's recycling program if one is available.
You can also research a cruise line's environmental record before booking. Some cruise lines publish annual sustainability reports that detail their waste management practices and environmental goals. Lines like Disney and Norwegian have made public commitments to reduce single-use plastics and improve wastewater treatment. Choosing a cruise line with a strong environmental record sends a market signal that passengers care about ocean health.
Frequently Asked Questions
Can cruise ships dump sewage in U.S. coastal waters?
No. Sewage must be treated through an approved marine sanitation device or stored in a holding tank and discharged at a port facility. Untreated sewage cannot be dumped anywhere in U.S. waters, including within 3 nautical miles of the coast. Beyond 12 nautical miles, treated sewage can be discharged if the ship is moving and the treatment system meets international standards.
What happens to the waste that is not dumped at sea?
Recyclables, hazardous waste, and general trash are stored on the ship and offloaded at ports. Cruise lines contract with waste management companies at each port to handle disposal. This is expensive—a large ship can spend thousands of dollars per port call on waste disposal—which is one reason some cruise lines have been tempted to dump illegally to save money.
Are there areas where cruise ships cannot dump anything?
Yes. Within 3 nautical miles of the U.S. coast, cruise ships cannot dump food waste, paper, or any other garbage. In some protected areas like the Great Lakes and certain marine sanctuaries, the rules are even stricter. A cruise ship in these zones must store all waste until it reaches a port with disposal facilities.
How do I report a cruise ship if I see it dumping illegally?
Contact the U.S. Coast Guard's National Response Center at 1-800-424-8802 or submit a report online at the Coast Guard website. Provide the ship's name, location, time, and a description of what you observed. The Coast Guard will investigate. You can also contact the Environmental Protection Agency or file a complaint with the cruise line itself, though the Coast Guard is the enforcement authority.
Do smaller cruise ships have different dumping rules than large ones?
The dumping rules explore to all commercial vessels, regardless of size. A small river cruise ship must follow the same regulations as a large ocean-going cruise ship. However, smaller ships generate less waste, so they may have an easier time storing waste until reaching port rather than dumping at sea.