UK ETS maritime: what ships and ports need to know

What has been decided

The UK Emissions Trading Scheme (UK ETS) has covered domestic maritime emissions since 1 July 2026. The legal basis is the Greenhouse Gas Emissions Trading Scheme (Amendment) (Extension to Maritime Activities) Order 2026, SI 2026/392, which amends the Greenhouse Gas Emissions Trading Scheme Order 2020.

The policy was set by the UK ETS Authority, which brings together the UK Government and the devolved governments of Scotland, Wales and Northern Ireland. Its main response on domestic maritime was published in November 2025, and the government published compliance guidance for operators in June 2026.

The first scheme year is a short one, running from 1 July to 31 December 2026. From 1 January 2027 scheme years follow the calendar year.

Which ships and voyages are covered

The scheme applies to ships of 5,000 GT and above. It regulates two activities: voyages between UK ports of call, including round trips that start and end at the same UK port, and in port activities at UK ports. In port emissions are covered even when the ship has arrived from, or is leaving for, a port outside the UK.

A port of call is a stop where passengers or crew embark or disembark, or cargo is loaded or unloaded. Stops only for refuelling, supplies, repairs, dry dock or shelter do not count. A voyage between two UK ports with a genuine call at a non UK port in between is not a UK voyage, and voyages to the Crown Dependencies and Overseas Territories are outside domestic scope.

The scheme covers CO2, methane (CH4) and nitrous oxide (N2O), expressed as CO2 equivalent. Operators can claim a zero emission factor for eligible fuels where the claim criteria are met and verified.

Exemptions and special treatment

Offshore ships were excluded up to and including 31 December 2026 and come into scope from 1 January 2027, in line with the EU ETS. Ships whose principal use is fish catching or fish processing are excluded, as are ships operating a Scottish ferry service to island and peninsula communities.

Military and other government non commercial activity is excluded. So are search and rescue, firefighting and humanitarian aid, coastguard work, publicly funded research and lighthouse services. Wooden ships of primitive build and ships propelled only by non mechanical means are also out of scope.

Voyages between Northern Ireland and Great Britain must be monitored and reported in full, but operators surrender allowances for only 50% of those emissions. Ships scheduled for more than 300 voyages in a scheme year may use simplified monitoring. The Authority will review the threshold, including a possible move to 400 GT, and the exemptions in 2028.

Who is responsible and the compliance cycle

The obligation falls on the maritime operator. By default this is the registered owner named on the certificate of registry. An ISM company becomes the maritime operator only under a legally binding written agreement covering operation of the ship, ISM Code compliance and UK ETS obligations, declared through the regulator's online system. Delegation cannot be backdated.

The regulator depends on where the operator is based. The Environment Agency regulates operators registered in England and those based outside the UK. SEPA covers Scotland, Natural Resources Wales covers Wales and the Northern Ireland Environment Agency covers Northern Ireland.

Operators must apply for an Emissions Monitoring Plan within 42 days of starting their first regulated activity. A verified Annual Emissions Report is due by 31 March each year, so the first is due by 31 March 2027. Allowances for both 2026 and 2027 are due by 30 April 2028, and from 2028 surrender is due by 30 April of the following year, through a Maritime Operator Holding Account in the UK ETS Registry.

Penalties for non compliance

An operator that fails to surrender enough allowances by the deadline pays an excess emissions penalty of £100 per allowance, multiplied by an inflation factor. The penalty applies even if the allowances are surrendered late, and the outstanding allowances must still be surrendered.

Regulators can also impose civil penalties for other failures, such as late reporting or breaching monitoring plan conditions. A deficit notice that is not complied with triggers a further mandatory penalty, and a daily penalty may apply.

What it means for ports and shore power

Because in port emissions are covered for every ship of 5,000 GT and above, the UK ETS puts a carbon price on fuel burned at berth in UK ports, including by ships on international voyages. Engine and boiler use while alongside now carries a direct compliance cost.

That changes the business case for shore power and other zero emission options at berth. Every tonne of fuel a ship avoids burning alongside reduces the allowances its operator must buy. Ports with frequent calls by large ferries, cruise ships and container ships are the most exposed.

The maritime sector receives no free allocation. The Authority raised the scheme cap by about 9.32 million allowances to account for maritime emissions, and all of these are added to auction volumes.

Proposals still under consideration

International voyages are not yet covered. In November 2025 the Authority consulted on including a share of emissions from voyages to and from the UK. The consultation closed on 20 January 2026, and as of November 2026 the outcome has not been published.

The consultation proposed a start in 2028. Operators would report 100% of emissions on voyages between a UK port and a non UK port but surrender allowances for 50%, while in port emissions would stay fully covered. The Northern Ireland and Great Britain deduction would end once international voyages enter the scheme. These points are proposals, not law.

The UK and the EU agreed in May 2025 to work towards linking their emissions trading systems, with both domestic and international maritime in scope of a linked scheme. As of November 2026 the two systems are not linked. The Authority has also said it will review maritime coverage once the IMO Net Zero Framework is adopted, which had not happened by November 2026.

UK ETS maritime compared with EU ETS maritime

The two schemes share a 5,000 GT threshold and the same three gases, but differ on geography, timing and enforcement.

A ship sailing between the UK and an EU port currently pays EU ETS on 50% of that voyage and UK ETS on its time at berth in the UK port.

Questions, answered

1. GOV.UK: UK Emissions Trading Scheme for maritime, how to comply
2. UK ETS Authority: Domestic maritime main Authority response (November 2025)
3. GOV.UK: UK ETS scope expansion, maritime sector (consultation and outcome)
4. GOV.UK: UK ETS scope expansion, emissions from international maritime voyages (closed consultation)
5. UK ETS Authority: International maritime consultation document (November 2025)
6. legislation.gov.uk: SI 2026/392, Extension to Maritime Activities Order 2026
7. legislation.gov.uk: Draft Extension to Maritime Activities Order 2026
8. ICAP: UK Emissions Trading Scheme factsheet
9. European Commission: Reducing emissions from the shipping sector
10. European Commission: Guidance Document No. 1 on maritime EU ETS
11. IMO: MEPC 84th session summary

Figures are checked against the regulation text and official sources listed above. Spotted something out of date? Write to media@dtfconference.com.