SeaReadyMaster's Companion

Decarbonisation · MARPOL Annex VI

IMO DCS reporting guide: deadlines, MEPC.385(81) data and how it compares with EU MRV, ETS and FuelEU

Under MARPOL Annex VI regulation 27, every ship of 5,000 GT and above collects its fuel oil consumption for each calendar year and reports it through its flag State to the IMO’s database — the IMO Data Collection System (DCS).

This guide sets out the yearly deadlines, the extra data required by MEPC.385(81) since 2025, how to reconcile bunker delivery notes, and how IMO DCS lines up with EU MRV, the EU ETS and FuelEU Maritime.

Updated · Written by SeaReady in our own words. Not affiliated with OCIMF, RightShip, CDI, any MoU or any administration — always check the current official documents.

IMO DCS reporting deadlines

Our summary of MARPOL Annex VI as amended. If the Statement of Compliance comes on 31 May, the database transfer is due within the following month.
StepDeadlineMARPOL Annex VI
Collect the data1 January to 31 December, every year (ships of 5,000 GT and above)Reg. 27.1
Report the year’s data to the flag State or ROWithin 3 months of the end of the year — by 31 MarchReg. 27.3
Statement of Compliance issuedWithin 5 months from the start of the year — by 31 MayReg. 6.6.4
Data sent to the IMO fuel oil consumption databaseWithin one month after the Statement of Compliance is issued (by the flag State)Reg. 27.9
Keep the Statement of Compliance on boardAt least 5 years. Valid for the year it is issued and the first 5 months of the nextReg. 9.12
Keep the detailed (disaggregated) dataReadily available for at least 12 months after the end of the yearReg. 27.8
Change of flag or company during the yearReport the data up to the transfer on the day it is completed, or as close to it as practical; the SoC follows promptlyRegs. 27.4–27.6, 6.7

IMO DCS vs EU MRV, EU ETS and FuelEU Maritime

MARPOL Annex VI regs. 6, 27; Reg. (EU) 2015/757 as amended (MRV); Directive 2003/87/EC as amended (ETS); Reg. (EU) 2023/1805 (FuelEU). The ETS rules are under review (Commission proposal of 17 July 2026) — check before relying on them.
IMO DCSEU MRVEU ETS (shipping)FuelEU Maritime
WhoShips of 5,000 GT and above, worldwideShips of 5,000 GT and above on EU voyages; from 2025 also general cargo and offshore ships of 400–4,999 GTCargo and passenger ships of 5,000 GT and above on EU voyages; offshore ships of 5,000 GT and above from 2027Ships above 5,000 GT on EU voyages
WhatFuel oil consumption, distance, hours (more detail from 2025 under MEPC.385(81))Monitoring, reporting and verification of emissionsBuying and surrendering emission allowances: 40% of 2024 emissions, 70% of 2025, 100% from 2026Greenhouse-gas intensity of the energy used: 2% below 91.16 g CO₂e/MJ from 2025, tightening in steps
ReportBy 31 March to the flag State or ROVerified emissions report by 31 March (it was 30 April up to 2024)Uses the verified MRV emissionsFuelEU report to the verifier by 31 January; verifier records by 31 March
DocumentStatement of Compliance by 31 MayDocument of compliance on board by 30 June—Penalty paid and FuelEU document of compliance by 30 June
Key deadline31 May (SoC)30 June (document of compliance)30 September: surrender the allowances30 April: pooling and borrowing; 30 June: document of compliance

What MEPC.385(81) added to the DCS report

Adopted on 22 March 2024 and in force since 1 August 2025 (early use invited from 1 January 2025), MEPC.385(81) amends Appendix IX of MARPOL Annex VI. On top of the yearly totals, the report now carries:

MEPC.385(81), Appendix IX, our summary.
New dataWhat to report
Fuel consumption by consumer typeMain engines, auxiliary engines and generators, oil-fired boilers, and others — per fuel type
Fuel consumed while not under wayPer consumer type — at anchor, alongside, drifting
Shore powerElectricity received from shore, in kWh
Laden distanceReported voluntarily
Transport work and CII dataFor ships that need a CII rating (regulation 28)

It also defines “gas fuel” (regulation 2.1.33), treats replacing a steam system with a diesel engine as a replacement engine for NOx purposes (regulation 13.2.2), and adds rules on sharing and public access to the database (regulations 27.14 and 27.15).

Reconciling bunker delivery notes for the DCS report

The bunker delivery note method in the 2024 SEEMP guidelines (MEPC.395(82), Part II) works like a stock account:

  1. Gather every BDN of the year. MARPOL Annex VI regulation 18 requires each BDN to be kept on board for 3 years and its sealed sample for at least 12 months.
  2. Read the tanks at the start and end of the year. Fuel used = fuel received on the BDNs + fuel on board at the start − fuel on board at the end.
  3. Take off any fuel discharged ashore (de-bunkered), using the Oil Record Book entries.
  4. For a voyage that runs over the year end, use tank readings at the ports of departure and arrival and spread the fuel by voyage days.
  5. Close any difference with evidence — supporting data must be backed by documents the verifier can see.
  6. Split by consumer type for MEPC.385(81) — with flow meters, tank monitoring, or by subtraction when only one consumer type is not measured.

SEEMP Part II: how fuel is measured

The ship’s SEEMP Part II (data collection plan) states which methods it uses. MEPC.395(82) lists:

  • Bunker delivery notes with tank readings, as above.
  • Flow meters on the fuel lines, with manual tank readings as back-up. The plan names each meter and the consumers it measures, and how meters are calibrated; keep calibration and maintenance records on board.
  • Bunker fuel oil tank monitoring — daily tank readings by automated gauges, soundings or dip tapes.
  • LNG carriers burning cargo: cargo tank monitoring with the custody transfer system, converting the LNG volume to mass (methane density 422 kg/m³).
  • Other cargo used as fuel: cargo tank monitoring.

What port State control checks

  • A Statement of Compliance on board and in date (the year of issue plus the first five months of the next).
  • The SEEMP with its Part II data collection plan and the flag State’s confirmation of compliance.
  • Fuel records that agree with each other: BDNs, the Oil Record Book, noon reports and flow-meter readings.
  • For CII ships, the rating and any corrective action plan — see the CII guide and the PSC action codes.

Questions seafarers ask

What are the IMO DCS reporting deadlines?

Under MARPOL Annex VI, the ship reports the previous calendar year’s fuel oil consumption data to its flag State or recognised organisation within three months of the year end — by 31 March. The flag State verifies it and issues the Statement of Compliance within five months from the start of the year — by 31 May. Within one month after issuing the Statement of Compliance, the flag State sends the data to the IMO Ship Fuel Oil Consumption Database.

Which ships must report under IMO DCS?

Ships of 5,000 gross tonnage and above, under regulation 27 of MARPOL Annex VI. Data collection started on 1 January 2019.

What changed with MEPC.385(81)?

MEPC.385(81), adopted on 22 March 2024 and in force since 1 August 2025 (with early use invited from 1 January 2025), adds detail to the DCS report: fuel consumption by consumer type (main engines, auxiliary engines and generators, oil-fired boilers, others), fuel consumed while not under way, shore power in kWh, voluntary laden distance and, for ships that need a CII rating, transport work.

What if a ship changes flag or company during the year?

The data for the part of the year up to the transfer is reported on the day the transfer is completed, or as close to it as practical, and the Statement of Compliance for that period is issued promptly (MARPOL Annex VI regulations 27.4–27.6 and 6.7).

How long is the DCS Statement of Compliance valid?

It is valid for the calendar year in which it is issued and the first five months of the next year, and it is kept on board for at least five years (regulation 9.12).

What is the difference between IMO DCS and EU MRV?

IMO DCS covers a ship’s fuel use worldwide and ends in a Statement of Compliance by 31 May. EU MRV covers emissions on voyages to, from and between EU ports: the verified emissions report is due by 31 March and the document of compliance must be on board by 30 June. EU MRV data is also what the EU ETS (allowances surrendered by 30 September) uses.

Open Bunkering & Fuel Changeover

Keep bunker delivery notes, fuel changeovers and fuel records together offline, ready for the DCS report and the verifier.

  • Offline SIRE 2.0, RightShip RISQ and PSC checklists
  • AI mock inspector and orals examiner
  • AI photo review of defects and ship-work photos
  • Rest-hour planner and record-book tools
Start your 14-day free trial See plansOpen this tool in the app

Crew $39.99/mo · Officer Pro $99.99/mo · Ship licence $899/mo per ship + 5% sales tax

14-day free trial, no card needed. Works offline at sea once installed.

Related guides

All 68 guides →