The Cruise Lines International Association (CLIA) today published its Environmental Technologies and Practices report. This edition highlights the ongoing and measurable progress made by CLIA member cruise lines in adopting environmental practices and technologies: from conducting trials and pilot projects with biofuels to increasing the number of ships equipped with systems that allow connection to the shore power grid, maximizing energy efficiency, using advanced wastewater treatment systems, providing potable water onboard, and other reported environmental practices.
“Year after year, the data shows that cruise lines continue to invest in technologies, fuels, and operational capabilities that make the fleet more efficient and better prepared for the future,” said CLIA President & CEO Bud Darr. “The progress reflected in this report is the result of the cruise lines’ ongoing investment and innovation worldwide: more efficient ships, engines that allow for greater fuel flexibility (multifuel engines), a commitment to grid connectivity, and advanced environmental systems.”.
“Cruise lines continue to invest in support of ambitious decarbonization goals by building ships that can use new, low-emission fuels, as well as a range of other environmental technologies and practices,” Darr adds. “To maximize the potential of these investments, fuel producers, governments, ports, energy providers, and other stakeholders will need to work together to create the right conditions for safe, competitively priced, renewable, and low-emission fuels to be available at scale and supported by the necessary supply infrastructure,” he concludes.
In August 2026, the 45 ocean-going cruise companies that are part of CLIA had a combined total of 327 ships and approximately 692,000 low berths, representing more than 90% of global capacity.
This year's report reflects the environmental technologies implemented on CLIA shipping lines' vessels throughout 2025, which translates to 297 ocean-going cruise ships, representing 96% of CLIA shipping lines' ships and 98% of their global capacity during that year.
Analysis of CLIA companies' current fleet indicates that the majority of ocean-going cruise ships (72%) are small or medium in size (
2039 (last reference year included in the current order book).
Emission Reduction and Operational Efficiency:
Multifuel Ships
• The number of CLIA member companies' ships capable of operating with multifuel engines – able to switch between conventional fuels and low- or zero-emission alternatives – both at sea and in port – has increased from a single vessel in 2018 to 30 today.
• According to the order book (August 2026), 31 multifuel ships (from CLIA member companies) are expected to be in service by the end of the year; this number will rise to 56 by the end of 2030.
• By 2039, it is estimated that 69 ships (from CLIA member companies) will be operating with multifuel engines; this figure includes the 30 vessels already in service and another 39 scheduled for delivery.
Adoption of alternative, low-sulfur, and low-emission fuels. Cruise lines continue to reduce their reliance on traditional heavy fuel oil as low-sulfur and low-emission alternatives emerge. These results reflect the combined impact of
more efficient ships, operational improvements, itinerary planning, and ongoing investment in multifuel engines, while also underscoring the need for zero- or low-emission marine fuels to be safe and available at scale.
• According to data reported to the International Maritime Organization (IMO) by passenger cruise ships2
, the use of HFO by cruise companies has fallen, from representing 74.2% of fuel in 2019, to 60.6% in 2024. Meanwhile, the combined use of fuels other than HFO – including marine diesel/gasoline, low or very low sulfur fuel, liquefied natural gas, and other reported options – has increased from 25.8% to 39.4%.
• The IMO data is consistent with the monitoring carried out by CLIA - through its ETP on the use of non-HFO fuels, which stood at 40.3% in 2025.
• Analysis of the latest data reported to the European Maritime Safety Agency via the EU THETIS-MRV3 database shows an improvement in the average efficiency indicators of cruise ships sailing in Europe. Between 2018 and 2025, the average fuel consumption of ships reporting fuel consumption and emissions to the EU-MRV database decreased by approximately 18.5%, and average CO2 emissions per ship fell by nearly 19.4%.
Connection to the electrical grid. OPS technology allows engines to be shut down when ships are in port (if the facilities are available) and can significantly reduce emissions, depending on the energy mix. This reduction in emissions (all included) can reach 98%, according to studies conducted by various ports and regulatory agencies, including the US Environmental Protection Agency.
• The number of ships (CLIA partner shipping companies) with the ability to connect to the shore power grid has more than tripled since 2018, going from 55 ships (25% of the total number of ships and 27.9% of the capacity) to 193 ships at present (65% of the ships that are part of this study and 72.5% of the reported capacity).
• In addition, plans are in place to equip another 47 ships with this system, which will be joined by 39 newly built vessels.
• Looking ahead to 2039, it is estimated that approximately 279 ships (74% of the fleet and 82% of capacity)
will be equipped with OPS (193 ships are already equipped with this technology, 47 will be upgraded and 39 will be newly built).
Currently, 40 cruise ports (less than 3%) worldwide offer grid connection. These projections underscore the ongoing investments made by the cruise industry to equip its ships with these systems. Achieving the full potential for reducing OPS/SEE emissions will depend on continued investment in port and energy infrastructure.
• According to the Fit for 55 EU legislative package, major European ports
must have Port Service Operators (PSOs) by 2030, which will further accelerate investment in
port infrastructure in the region.
Selective catalytic reduction systems. They reduce nitrogen oxide emissions, helping ships comply with IMO Tier III NOx emission standards.
• The number of ships (CLIA companies) equipped with SCR has grown considerably,
from seven ships in 2018 (3.2% of capacity) to 96 ships in 2026 (32.3% and 27.6% of ships and reported capacity).
Water Management:
Water Purification. The use of state-of-the-art systems allows most CLIA member shipping companies to purify most of the water they need on board instead of having to obtain it in ports and destinations, where this resource is limited. This is made possible by various technologies and practices such as steam evaporation systems, reverse osmosis, aeration, and other systems that promote water conservation.
• Today, 239 ships (98.7% and 99.9% of the vessels and reported capacity) can purify water on board.
• Of these ships, 218 (73.4% and 83.3% of the vessels and reported capacity) can purify 100% of the water they need on board, which means that theoretically they can operate without needing to replenish their water supply.
Advanced Wastewater Treatment Systems (AWTS). All ships of CLIA member cruise lines currently sailing have wastewater treatment systems, and most use advanced wastewater treatment systems that exceed the requirements set out in Annex IV of MARPOL. Furthermore, as part of their comprehensive approach to sustainability, CLIA shipping lines have committed to not discharging untreated wastewater during their routine operations anywhere in the world.
• Within the fleet of CLIA member shipping companies, 249 vessels (83.8% and 86.2% of vessels and reported capacity, respectively) are equipped with approved and operational AWSTs, capable of meeting or exceeding the parameters established by the IMO in Annex IV of MARPOL. This represents an increase from 136 vessels in 2018 to 249 in 2026, reflecting ongoing investment in advanced wastewater treatment technologies across the fleet.
• Of this number, 124 ships have AWST capable of meeting the (stricter) standards set by the IMO in Annex IV for the Baltic Special Area, compared to 16 ships that met these requirements in 2018.
Waste Management:
Alongside the adoption of low-emission fuels and the increased energy efficiency of the fleet, shipping companies continue to implement advanced technologies and practices for onboard waste management, designed to reduce, recycle, and reuse waste, thereby decreasing the volume of waste. Some ships are already capable of recycling or reusing virtually all the waste generated onboard.
• Systems that transform waste into fuel: These are still an emerging technology in onboard waste management. They are currently used on 7 ships (12,276 low berths or 1.8% of the reported fleet) and convert waste into energy that is subsequently used onboard.
• Systems that allow the use of natural food waste in biodigesters: these are currently used on 137 vessels (46.1% of ships and 51.3% of declared capacity) and reduce the volume of food waste on board, promoting more efficient management. This figure contrasts with the 103 ships registered in 2022 (42.7% and 44.7% of ships and capacity, respectively), when monitoring of this indicator began.
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