CLIA releases annual environmental report

10 September 2025 – Cruise Lines International Association (CLIA), the leading voice of the global cruise industry, today released its annual Environmental Technologies and Practices (ETP) report. The report provides a profile of the CLIA-member oceangoing cruise line fleet and highlights environmental technologies in use by CLIA-member ocean-going cruise lines, which comprise more than 90% of the cruise sector.

This year’s report shows continuous and measurable progress by CLIA-member cruise lines as they advance an ambitious environmental agenda—from testing and piloting biofuels, to investing in fuel-flexible engines, to the increasing use of lower emissions fuels, and maximizing energy-efficiency measures.

“Cruise lines are early adopters and innovators of maritime technology — examples include advanced wastewater systems, onshore power supply, air lubrication systems, and the newest generation of dual-fuel engines—from which other sectors of maritime also benefit,” said Bud Darr, president and CEO of CLIA. “Cruise lines are investing tens of billions of dollars to build the fleet of the future, including more than 80 new ships on order worldwide that feature these and other innovations. These orders represent tangible steps that are significantly enhancing the operational capability and efficiency of the collective global cruise ship fleet of our members,” Darr added.

Highlights from the industry’s 2025 Environmental Technologies and Practices Report

Fleet Profile of CLIA-member Cruise Lines (source: CLIA membership profile data)

• CLIA-member Cruise Lines: As of August 2025, 45 cruise lines, representing 90% of global oceangoing capacity, are members of CLIA. Combined, these cruise line members operate 310 ships and 637,847 lower berths, compared to 303 ships and 645,034 lower berths last year.

• Fleet Profile: Analysis of the current CLIA member cruise line fleet indicates that the majority of oceangoing ships—73% — are small to mid-size ships (<3,000 lower berths), with the percentage of ships by size remaining relatively balanced through at least 2036 (based on the orderbook, which runs through December 2036):

• Small ships (<1,000 lower berths): 34.2% in 2025; 34.1% in 2036.
• Mid-size ships (1,000 to 3,000 lower berths): 38.4% in 2025; 35.5% in 2036.
• Large ships (>3,000 lower berths): 27.4% in 2025; 30.4% in 2036.

Pursuit of Net-Zero Emissions and Operational Efficiency

• Multi-fuel capable ships: Multi-fuel engine technology provides the fuel flexibility needed to utilize zero- and near-zero emission fuels as they become available, at scale, with little to no engine modifications.

• The number of ships operating with multi-fuel engines that can switch from conventional fuels to zero- and near-zero emission fuels both in port and at sea has increased from just one ship in 2018 to 19 ships today. All 19 are dual-fuel ships.¹
• By year-end 2025, 23 ships with fuel-flexible engines are forecast to be in service, including the first cruise ship with tri-fuel capability.
• Through 2036, 32 dual-fuel ships are forecast to launch, including seven capable of using methanol and 25 capable of using LNG.

• Uptake of alternative, zero- and near-zero emissions fuel pathways: Cruise lines continue to increase their use alternatives to Heavy Fuel Oil as options begin to emerge, including biofuels, LNG, and others, as exemplified by the delivery of one ship in 2024 specified for methanol use by 2026, and another slated for delivery by the end of this year.

• Onshore power supply (OPS) connectivity: Also referred to as shoreside electricity (SSE) capability, allows ships to turn off their engines while in port for emissions reductions of up to 98% (with all emissions covered) depending on the mix of energy sources, according to studies conducted by a number of the world’s ports and the U.S. Environmental Protection Agency.

• The number of CLIA-member cruise line ships with the ability to utilize OPS has nearly doubled since 2018, when 55 ships, representing 25% of the fleet and 28% of capacity, had OPS capability. Today, 166 ships are able to plug in at port, a 12% increase from the prior year. These ships represent 58% of the fleet and 65% of capacity.
• By 2036, 273 ships that can connect to OPS are expected to be in service (based on the number of ships scheduled to be retrofitted and new ships on the order book specified for OPS connectivity). This includes 166 currently with OPS, plus 59 currently in service scheduled for retrofit and each of the 48 CLIA-member cruise ships on the 2025-2036 order book.
• Currently 41 of the ports worldwide where cruise ships call (fewer than 3%) have a cruise berth with OPS, an increase of eight ports since last year.
• Europe has led the expansion over the last 12 to 18 months—with OPS being launched in six additional cruise ports, and the UK and North America each added one new cruise port with OPS.
• There are 19 ports that have secured funding for OPS and 26 more with plans to do so.
• As part of the EU’s Fit for 55 decarbonization regulations, by 2030 major ports in Europe will be required to have shoreside power, which will further accelerate port infrastructure investment in that region.
• To view a map of ports that have at least one cruise berth with OPS, please go to this link.

• Selective Catalytic Reduction Technology (SCR): SCR reduces particulate matter and nitrogen oxide emissions, thus helping ships to meet IMO Tier III classification standards for nitrogen oxide emissions (NOx).

• The number of CLIA-member cruise line ships with SCR systems has increased tenfold, from 7 ships in 2018, representing 3% of the fleet and 3.2% of capacity, to 81 ships, representing 28.5% of the fleet and 22.3% of capacity.

Shipboard Water Production

• Freshwater Production: State-of-the-art systems that enable most CLIA-member cruise lines to produce the majority of their water needs on board rather than drawing from ports and destinations where resources may be limited. This is made possible by a range of environmental practices that include steam evaporation, reverse osmosis, aeration, and other systems that enable cruise lines to conserve water.

• Today, 279 ships, representing more than 98.2% of the fleet and 99.9% of global capacity, are able to do so.

Wastewater Treatment

• Advanced Wastewater Treatment Systems (AWTS): The majority of CLIA member cruise ships sailing today utilize advanced wastewater treatment systems (AWTS) which are capable of exceeding MARPOL Annex IV requirements. In addition, as part of their overarching sustainability focus, cruise lines have committed to not releasing untreated sewage anywhere in the world during normal operations.

• Across the CLIA cruise line member fleet, 234 ships, representing 82.4% of the fleet and 85.4% of global passenger capacity, are equipped with AWTS, a 4% increase in the number of ships and passenger capacity year-over-year, and a 72% and 71% increase, respectively, since 2018.
• Today, more than one-third of the ships equipped with AWTS are capable of meeting the more stringent wastewater standards of the Baltic Sea Special Area.
• By 2036, 273 ships and 685k LBs of capacity are specified to have AWTS.

Waste Management

• Waste Management: Alongside the uptake of lower-emissions fuels and increasingly energy efficient fleets, cruise lines are beginning to deploy a new generation of shipboard waste management technologies—with some ships able to recycle or repurpose nearly all waste generated on board. Some of the state-of-the-art systems currently used on cruise ships include:

• Waste-to-energy gasification systems: Currently in use on eight cruise ships, these systems convert waste into usable energy to support the ship’s operations, thus reducing waste sent to landfills and decreasing the ship’s energy demand.
• Microbial digesters for food waste: Currently in use on 128 cruise ships, representing 45% of member ships and 52% of capacity, to significantly reduce food waste, few of these types of waste management systems were present on cruise ships five years ago.

Notes:

¹ Regarding multi-fuel capable ships: Virtually all engines using conventional fuels such as HFO, VLSFO, and MGO are capable of operating on renewable drop-in biofuels and synthetic diesel both in port and at sea, and this remains an important component of decarbonization. For the purposes of tracking year-over-year technological advancements, only ships equipped with newer multi-fuel engines designed to operate on zero- and near-zero emission fuels are included in this metric.

About the report:

• The CLIA Environmental Technologies and Practices Report has been published annually since 2018 and provides highlights of environmental technologies in use by CLIA-member cruise lines.
• Each year the report may include additional technologies tracked that were not tracked in prior years. To view the summary chart of results, please go to this link.
• This year’s report includes highlights of environmental technologies and practices currently in use by CLIA-member cruise lines and is not intended to be a comprehensive review of all of the technologies and practices cruise lines employ.
• All information provided in the annual ETP report is sourced from the annual ETP survey report, unless otherwise noted.
• To view a list of CLIA-member cruise lines, please go to this link.