Can Cruise Ships Dump Garbage in the Ocean?

You may have seen images of pristine oceans — but did you know that cruise ships can legally dump certain types of waste at sea? Despite decades of environmental progress, oceans are still under threat from cruise ship pollution. 

U.S. law requires cruise ships to treat waste within about 3.5 miles of shore—but beyond that, there are no restrictions on dumping polluted sewage and graywater.  

Researchers have estimated that over a billion gallons of sludge made from excrement and food scraps are released into the ocean every year by cruise lines. 

What types of waste do cruise ships dump? 

Cruise ships produce enormous amounts of waste. Some of it ends up at sea, either legally or illegally. Types include: 

• Sewage (black water): Wastewater from toilets. Can contain bacteria, viruses, and nutrients that harm marine life. 
• Greywater: From sinks, showers, laundry, and kitchens. Contains detergents, oils, and food residues. 
• Solid waste: Plastics, paper, food scraps, and packaging. Plastics break down into microplastics that persist for decades. 
• Hazardous waste: Oils, paints, and chemicals used in cleaning or maintenance. 

Even treated wastewater can harm delicate ecosystems, especially near coral reefs and coastal areas. Cruise ships don’t have the resources or the facilities to filter out many of these toxic substances. They end up in the habitats of many coastal animals from otters to dolphins to whales, leading to reproductive problems, illness and population decline. 

Are there laws against dumping? 

International and national laws regulate what ships can dump: 

• MARPOL prohibits most garbage dumping within 12 nautical miles of shore. Beyond that, some discharge is allowed. 
• In the United States, the Clean Water Act limits dumping in U.S. waters, but enforcement can be inconsistent. 
• Loopholes allow certain treated sewage and greywater to be discharged offshore legally. 

In practice, enforcement is difficult, and self-regulation by the cruise industry often falls short. While it’s illegal according to U.S. and international maritime law, many companies have proven they don’t care and have been caught illegally spewing plastic into the sea. In 2019, Carnival Cruise Lines was fined $20M for probation violations and illegal dumping, including plastic. The cruise industry has been accused of having some of the worst waste management practices worldwide, and while the law says cruise ships have to offload plastic at a port, we know that many are doing just the opposite. 

How cruise ships manage waste onboard 

Modern cruise ships have waste management systems: 

• Wastewater treatment plants onboard (like miniature sewage plants) 
• Incineration of some garbage 
• Recycling programs 

However, older ships or improperly maintained systems may still discharge untreated or partially treated waste. 

Environmental impacts of ocean dumping 

Dumping waste into the ocean can cause: 

• Harm to marine life: Toxins and bacteria can kill fish, coral, and other organisms. 
• Microplastic pollution: Plastics break down slowly, entering food chains. 
• Algal blooms: Nutrient-rich wastewater can trigger harmful blooms that suffocate marine life. 
• Ecosystem damage: Coral reefs and coastal areas are particularly vulnerable. In George Town, Grand Cayman, three hundred acres of coral were lost to cruise ships anchors. 

Even small discharges add up, threatening ocean health globally. 

Why this matters to you 

Cruise ships aren’t just a vacation problem — they’re a public and environmental concern. Ocean pollution affects: 

• Seafood safety 
• Coastal tourism 
• Marine biodiversity 
• Climate resilience in marine ecosystems 

What can be done? 

You can take action to reduce cruise ship pollution: 

• Support stricter regulations for offshore dumping 
• Demand accountability from cruise lines 
• Choose environmentally responsible cruises or travel alternatives 

Friends of the Earth is campaigning for a cleaner ocean — and public pressure is key to holding polluters accountable.