Mariners Digest
IMO DCS changes: the amended Appendix IX data fields and when each one applies
Since 2019 every ship of 5,000 GT and above has reported its yearly fuel oil consumption to the IMO Data Collection System (DCS). The list of what it reports, MARPOL Annex VI Appendix IX, has been rewritten three times: CII and EEXI fields from 1 May 2024, fuel per consumer, transport work and onshore power from 1 August 2025 (collected from 1 January 2026 on most flags), and a clarification adopted at MEPC 84 that enters into force on 1 September 2027.
The three Appendix IX amendments and their dates
| Resolution | Adopted | In force | What it adds to the report |
|---|---|---|---|
| MEPC.362(79) | 16 Dec 2022 | 1 May 2024 (early application invited from 1 Jan 2024) | Attained EEXI, ice class and the CII block: required and attained CII, the A to E rating, trial indicators |
| MEPC.385(81) | 22 Mar 2024 | 1 Aug 2025 (early application invited from 1 Jan 2025) | Fuel per consumer type, fuel used not under way, laden distance (voluntary), onshore power, transport work, innovative technology |
| MEPC.407(84) | 1 May 2026 | 1 Sep 2027 | Separate reporting periods for regulations 27 and 28, “Fired Boiler(s)”, new database access rules |
Sources: IMO, resolution MEPC.362(79), resolution MEPC.385(81) and resolution MEPC.407(84) (MEPC 84/16/Add.1, annex 3) (all PDF); read on 13 November 2026.
How the IMO DCS works
- Ships of 5,000 GT and above collect the Appendix IX data for each calendar year, by the methodology set out in Part II of their SEEMP (regulation 27, adopted by resolution MEPC.278(70) in October 2016; collection since 1 January 2019).
- After the year ends the ship aggregates the data and reports it to its flag Administration.
- The flag verifies the data and issues a declaration of compliance to the ship by 31 May.
- The flag transfers the data to the IMO Ship Fuel Oil Consumption Database, a module of GISIS, by 30 June.
- IMO reports to MEPC every year. Since 2023 the same data has been used to calculate each ship’s CII rating.
Source: IMO, Data collection system for fuel oil consumption of ships; read on 13 November 2026.
The Appendix IX fields in force now (MEPC.385(81))
| Section | Field | New in 2025? |
|---|---|---|
| Identity | IMO number; start and end date of the period reported | No |
| Ship | Year of delivery, ship type, GT, NT, DWT, rated power of engines over 130 kW, attained EEDI, attained EEXI, ice class | No (EEXI and ice class since 2024) |
| Fuel | Total consumption by fuel type in tonnes, and the method used to measure it | No |
| Fuel per consumer | Consumption by fuel type for main engines, auxiliary engines and generators, oil-fired boilers, others | Yes |
| Not under way | Consumption while not under way, by fuel type and the same consumer types | Yes |
| Distance and time | Total distance travelled (nm); hours under way | Renamed only |
| Laden distance | Laden distance travelled (nm), on a voluntary basis | Yes |
| Shore power | Total amount of onshore power supplied (kWh) | Yes |
| CII ships only | Total transport work | Yes |
| CII ships only | Applicable CII (AER or cgDIST), required CII, attained CII before and after correction, rating A to E, trial indicators (EEPI, cbDIST, clDIST, EEOI) | No (since 2024) |
| CII ships only | Innovative technology installed, if any (category A, B-1, B-2, C-1, C-2) | Yes |
Sources: IMO, resolution MEPC.385(81), annex, Appendix IX, compared with resolution MEPC.362(79); read on 13 November 2026. Field names paraphrased; Appendix IX is authoritative.
When ships started collecting the enhanced data
IMO guidance MEPC.1/Circ.913 (21 October 2024) sets out two routes, depending on the flag:
- Flags applying the amendments early (1 January 2025): the SEEMP was revised and verified before 1 January 2025 (or before delivery for ships delivered later), and the enhanced data is collected for the whole of 2025 onwards.
- Flags applying them on entry into force (1 August 2025): 2025 data is collected at the old level of detail and reported in early 2026; the SEEMP was to be revised and verified before 1 January 2026, and the enhanced data is collected from 1 January 2026. Ships delivered on or after 1 August 2025 collect enhanced data from delivery.
- All portions of one calendar year are collected and reported at the same level of detail. Ships planning to fit flow meters or other new methods were to do so within the same time frame.
Source: IMO, MEPC.1/Circ.913 (PDF); read on 13 November 2026. Your flag Administration’s notice says which route it took.
What MEPC 84 changed (in force 1 September 2027)
Resolution MEPC.407(84), adopted on 1 May 2026, is deemed accepted on 1 March 2027 and enters into force on 1 September 2027. For the DCS it:
- gives the report two pairs of start and end dates, one “for the purpose of regulation 27” (fuel data) and one “for the purpose of regulation 28” (CII);
- replaces “Oil-fired Boiler(s)” with “Fired Boiler(s)” in the consumer split;
- rewrites regulation 27.11 to 27.17 on access: the flag sees all of its ships’ past data; Parties get a non-anonymised database for their own analysis, but a flag may require its express approval before its ships’ data are included; IMO keeps an anonymised public database; data may be shared with research bodies under strict confidentiality; and a company can ask for its own ships’ reports to be made public.
The same session also adopted amendments to the 2024 SEEMP Guidelines on the data-collection plan in SEEMP Part II (resolution MEPC.413(84)).
Sources: IMO, resolution MEPC.407(84) and resolution MEPC.413(84) (PDF); read on 13 November 2026.
What this means on board
- Check that the SEEMP Part II on board is the revised, verified version that describes the per-consumer method.
- Log fuel by consumer (main engine, auxiliaries and generators, boilers, others), and separately while not under way.
- Record hours under way and distance; laden distance is voluntary.
- Note any onshore power taken in port, in kWh.
- Keep the declaration of compliance for the previous year on board once the flag issues it (by 31 May).
Drawn from the IMO sources above. Your company’s SEEMP and flag instructions govern the detail.
Questions
Which ships must report to the IMO DCS?
Every ship of 5,000 gross tonnage and above, under regulation 27 of MARPOL Annex VI. Ships have collected fuel oil consumption data for each calendar year since 2019, using the methodology described in their SEEMP.
When did the enhanced IMO DCS data fields become mandatory?
The amendments in resolution MEPC.385(81) entered into force on 1 August 2025. IMO guidance (MEPC.1/Circ.913) says ships of flags that applied them from that date collect the 2025 data at the old level of detail and the enhanced data from 1 January 2026. Flags that applied them early did so from 1 January 2025.
What new data does Appendix IX now ask for?
Fuel oil consumption by fuel type for each consumer type (main engines, auxiliary engines and generators, boilers, others), the same split for fuel used while not under way, total distance travelled, laden distance on a voluntary basis, hours under way, onshore power supplied in kWh and, for ships under the CII regulation, total transport work.
Do ships need to revise the SEEMP for the new data?
Yes. MEPC.1/Circ.913 says each ship should have its SEEMP revised and verified by the Administration or its recognized organization to describe how the more detailed data will be collected, before it starts collecting that data. For flags applying the amendments from 1 August 2025, that meant before 1 January 2026.
What did MEPC 84 change in the IMO DCS?
Resolution MEPC.407(84), adopted on 1 May 2026, adds separate start and end dates for the regulation 27 and regulation 28 reporting periods, renames Oil-fired Boilers to Fired Boilers, and rewrites the rules on who can access the database. It enters into force on 1 September 2027.
Who can see a ship's IMO DCS data?
The flag Administration sees all reported data for its ships, and IMO keeps an anonymised database for public users. Under the MEPC.407(84) text in force from 1 September 2027, Parties get access to a non-anonymised database, but a flag State may require its express approval before its ships' data are included. A company can ask IMO to make its own ships' reports public.
Mariners Digest is made by CryoSim. It is not affiliated with or endorsed by IMO. This page summarises IMO’s published documents in CryoSim’s own words and is not legal or technical advice; MARPOL Annex VI and your flag State’s requirements always take precedence. Published 2026-11-13, updated 2026-11-13. See also CII rating in 2026, EEXI and SEEMP Part III, EU ETS for shipping and Mariners Digest.
