# IMO DCS | Navatom Maritime Glossary
The IMO Data Collection System (IMO DCS) is a global, mandatory scheme under MARPOL Annex VI. Ships of 5,000 GT and above must collect their annual fuel oil consumption data. They report it to the IMO through their flag states.

URL: https://navatom.com/glossary/imo-dcs

## Synonyms
- IMO Data Collection System
- IMO Fuel Oil Data Collection System

## Definition
## What Is IMO DCS?
The IMO Data Collection System (IMO DCS) is a global mandatory scheme established under MARPOL Annex VI, Regulation 22A, requiring ships of 5,000 gross tonnage and above engaged in international voyages to collect and report fuel oil consumption data on an annual basis. The system was introduced as part of the IMO's three-step approach to reducing greenhouse gas emissions from shipping — data collection, data analysis, and decision-making on further measures.
Data collection began on 1 January 2019, and the information gathered feeds directly into the calculation of Carbon Intensity Indicator (CII) ratings.
## Data Points and Reporting Process
Ships subject to IMO DCS must collect data on fuel oil consumption by fuel type, distance travelled, and hours underway for each calendar year. This data collection methodology is documented in the ship's SEEMP Part II, which specifies the methods used for measuring fuel consumption — whether through BDN-based tracking, flow meters, or tank soundings.
At the end of each reporting period, the aggregated data is compiled into a report and submitted to the ship's flag state administration, which verifies the data and transfers confirmed reports to the IMO's GISIS (Global Integrated Shipping Information System) database for anonymized analysis.
## IMO DCS vs. EU MRV
While IMO DCS and the EU Monitoring, Reporting, and Verification (EU MRV) regulation share the same fundamental goal of collecting ship emissions data, they differ in scope and methodology. IMO DCS is global and reports through flag state administrations, while EU MRV applies specifically to voyages to, from, and between EU/EEA ports and requires third-party verification by accredited bodies.
The EU MRV also collects additional data points including cargo carried and CO2 emissions per transport work. Ships trading in European waters must comply with both systems, creating a dual reporting obligation that can be burdensome without proper software support.
Ship management software automates IMO DCS compliance by continuously collecting fuel consumption readings from onboard systems, calculating distance and hours underway from voyage data, and generating the required annual reports in the correct format for flag state submission. Integrated platforms can simultaneously prepare both IMO DCS and EU MRV reports from the same underlying data, eliminating double entry and reducing the risk of discrepancies between the two submissions.

## Related Terms
- [EU MRV](https://navatom.com/glossary/eu-mrv) — The EU Monitoring, Reporting and Verification (MRV) Regulation is Regulation (EU) 2015/757. It applies to ships over 5,000 gross tonnage calling at ports in the European Economic Area. Their operators must monitor, report and verify the ships' CO2 emissions. Since 2024 it also covers methane and nitrous oxide.
- [CII Rating](https://navatom.com/glossary/cii-rating) — The Carbon Intensity Indicator (CII) is an IMO operational measure of how efficiently a ship carries cargo for the CO2 it emits. Each ship gets a rating from A to E, on a scale that tightens every year.
- [SEEMP](https://navatom.com/glossary/seemp) — The Ship Energy Efficiency Management Plan (SEEMP) is a mandatory operational plan under MARPOL Annex VI. Shipping companies use it to manage and improve the energy efficiency of their vessels over their whole working life.