Reference metadata describe statistical concepts and methodologies used for the collection and generation of data. They provide information on data quality and, since they are strongly content-oriented, assist users in interpreting the data. Reference metadata, unlike structural metadata, can be decoupled from the data.
Transport Section, Central Statistics Office, Skehard Road, Cork, Ireland
1.6. Contact email address
Confidential because of GDPR
1.7. Contact phone number
Confidential because of GDPR
1.8. Contact fax number
Confidential because of GDPR
2.1. Metadata last certified
26 September 2025
2.2. Metadata last posted
26 September 2025
2.3. Metadata last update
26 September 2025
3.1. Data description
Maritime transport data refer to gross weight of goods (in tonnes), passenger movements (in number of passengers) as well as for vessel traffic (in number of vessels and in gross tonnage of vessels).
Data files are received quarterly from the responding ports and organisations responsible for maritime data.
3.2. Classification system
The following classifications are applicable:
Maritime Coastal area: the nomenclature is based on the Geonomenclature (the country nomenclature for the external trade statistics of the Community and statistics of trade between Member States, originally drawn up by the Council Regulation (EEC) N°1736/75) in force in the year to which the data refer (RAMON).
Ports: the codes used are the official UN/LOCODEs, when they exist. If a port does not have an official UN/LOCODE a provisional (numeric) code is attributed to the port. As soon as an official UN/LOCODE is attributed by the United Nations Economic Commission for Europe (UNECE) to the port at the request of the competent national authority, the provisional (numeric) code is replaced by the final official one. In exceptional cases (see for example one-port transport or special aggregation for minor ports) permanent numeric codes are attributed to special locations or activities. The code list of UN/LOCODE is available by country through the following Unece website. According to the relevant directive, Eurostat draws up a list of ports, coded and classified according to countries and maritime coastal areas. The list of ports is included in implementing legal acts and as such is published in the Official Journal of the European Union (the "official" list). The most recent list of ports published in the Official Journal is found in Commission Decision (EU) 2018/1007
Nationality of registration of vessels: the nomenclature used is the Geo-nomenclature (the country nomenclature for the external trade statistics of the Community and statistics of trade between Member States, originally drawn up by the Council Regulation (EEC) N°1736/75) in force in the year to which the data refer (RAMON).
The type of ship classification is harmonised with an internationally agreed International Classification of Ship by Type (ICST).
Port -A place having facilities for merchant ships to moor and to load and/or unload cargo or to disembark and/or embark passengers to or from vessels, usually directly to a pier. Statistical Port -A statistical port consists of one or more ports, normally controlled by a single port authority, which can record ship, passenger and cargo movements. Reporting Port-A statistical port for which statistics of inward and outward maritime transport flows are compiled. Main port -A main port is a statistical port which has annual movements of no less than 200 000 passengers or recording more than one million tonnes of cargo. For ports selected on the basis of only one of these cargo or passenger criteria, detailed statistics are required only for that transport. Maritime coastal area (MCA) -A maritime coastal area is defined as a contiguous stretch of coastline, together with islands offshore. Within a country, an MCA is defined either in terms of one or more ranges of ports along its coastline, or in terms of the latitude and longitude of one or more sets of extremities of the coastal area. Riverbanks can be included. Normally the coastline of each country is allocated to a single maritime coastal area and the coastlines of more than one country may form a single maritime coastal area. There are some exceptions. For example, the USA is separated into a number of maritime coastal areas to cover its overall coastline. For some countries, two separate stretches of coastline may be counted as one maritime coastal area, as, for example, the Atlantic and Pacific coastlines of Mexico. Carriage of goods and passengers by sea -The movement of goods and passengers using seagoing vessels, on voyage which are undertaken wholly or partly by sea. The scope of the Maritime Directive 2009/42/EC also includes goods:
Shipped to offshore installations;
Reclaimed from seabed and unloaded in ports.
Bunkers and stores supplied to vessels shall be excluded from the scope.
Seagoing vessel -Floating marine structure with one or more surface displacement hulls. In the context of the Directive, sea-going vessels are vessels other than those which navigate exclusively in inland waters or in waters within, or closely adjacent to, sheltered waters or areas where port regulations apply. Nationality of registration of seagoing vessel (Flag state) -Every ship is entered in a registry (i.e. list) of ships. Registries are maintained by many countries, each having a set of rules regarding safety procedures, inspection schedules, manning numbers and nationalities for crew and officers, training requirements, etc. Ship-owners select which registry to use based on the balance between the relative cost implications of the rules of each registry and possible penalties from insurance assessments dependent on these rules. Type of cargo- The type of cargo classification, set according to the UNECE - Codes for types of cargo, packages and packaging materials, Recommendation 21, Geneva, March 1986, describes how the goods are being transported in terms of the vessels being used and the port facilities required to handle them. It is therefore very different from the categories of goods classification. Freight container-Special box to carry freight, strengthened and stackable and allowing horizontal or vertical transfers.
Swap bodies are excluded. Although without internal volume flats used in maritime transport should be considered to be a special type of container and therefore are included here. For a fuller description, reference should be made to ISO 668 and 1496.The related term "container cargo" refers to containers, with or without cargo, which are lifted on or off the vessels which carry them by sea.
Ro-Ro unit- This means wheeled equipment for carrying cargo, such as a truck, trailer or semi-trailer, which can be driven or towed onto a vessel. Port or ships' trailers are included in this definition. Classifications should follow United Nations ECE Recommendation No 21 'Codes for types of cargo, packages and packaging materials'. Live animals on the hoof are included. Vehicles being transported as cargo as opposed to a means of transport for freight are recorded in the separate headings of the Ro-Ro cargo classification, when they are rolled on or rolled off a vessel on their own wheels. Ro-Ro cargo -This means goods, whether or not in containers, on Ro-Ro units, and Ro-Ro units, which are rolled on and off the vessels, which carry them by sea. Gross weight of goods -The gross weight of each consignment is the weight of the actual goods together with the immediate packaging in which they are being transported from origin to destination, but excluding the tare weight of containers or Ro-Ro units (e.g. containers, swap bodies and pallets containing goods as well as road goods vehicles, wagons or barges carried on the vessel). This measure of quantity is different from that used in trade statistics, namely the net weight of goods and different from statistics collected on other transport modes where the tare weight is included. Where goods are transported in a road goods vehicle, in a container, or other intermodal transport unit, the gross weight of the goods does not include the tare weight of the transport unit. Gross tonnage -This means the measure of the overall size of a ship determined in accordance with the provisions of the International Convention on Tonnage Measurement of Ships, 1969. Passenger Any person who makes a sea journey on a merchant ship. Service staff assigned to merchant ships is not regarded as passengers. Non-fare paying crewmembers travelling but not assigned and infants in arms are excluded. Cruise passenger -This means a sea passenger making a sea journey on a cruise ship. Passengers on day excursions are excluded. Cruise ship -This means a passenger ship intended to provide passengers with a full tourist experience. All passengers have cabins. Facilities for entertainment aboard are included. Ships operating normal ferry services are excluded, even if some passengers treat the service as a cruise. In addition, cargo-carrying vessels able to carry a very limited number of passengers with their own cabins are also excluded. Ships intended solely for day excursions are also excluded. Cruise passenger excursion -This means a short visit by a cruise passenger to a tourist attraction associated with a port while retaining a cabin on board.
3.5. Statistical unit
The data used in the domain are collected at port level.
3.6. Statistical population
Detailed data are provided for ports handling more than one million tonnes of goods or recording more than 200 000 passenger movements annually (Main ports). The other ports are required to provide summary data. However, detailed data may be included also for minor ports on a voluntary basis.
3.7. Reference area
Maritime ports located in the Republic of Ireland
3.8. Coverage - Time
Data available from 1995
3.9. Base period
Not applicable.
The units used depend on the variables collected within each data set and are: gross weight of goods expressed in thousands of tonnes; number of passengers in thousands, number of vessels.
TEUs: Twenty feet equivalent units, expressed in units or in thousands depending on the table. TEU calculation coefficients:
20-ft freight units (1 TEU).
40-ft freight units (2 TEU).
Freight units over 20-ft and under 40-ft in length (1.5 TEU).
Freight units over 40-ft long (2.25 TEU).
Quarters for datasets A1, A2, C1, C2, D1, F1 and F2. Whole calendar years for datasets A3, B1 and E1.
Reference period 2021
6.1. Institutional Mandate - legal acts and other agreements
The dissemination is based on the terms of Commission Decision 2001/423/EC on arrangements for publication or dissemination of the statistical data collected pursuant to Council Directive 95/64/EC on statistical returns in respect of carriage of goods and passengers by sea.
6.2. Institutional Mandate - data sharing
Not applicable.
7.1. Confidentiality - policy
National level:
The confidentiality of all information provided to the CSO by individual respondents is guaranteed by law under the 1993 Statistics Act (information provided will be treated as strictly confidential in accordance with Section 33 of the Statistics Act 1993.
(recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society.
7.2. Confidentiality - data treatment
National level:
The confidentiality of all information provided to the CSO by individual respondents is guaranteed by law under the 1993 Statistics Act (information provided will be treated as strictly confidential in accordance with Section 33 of the Statistics Act 1993.
European level:
Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society.
Article 4 of Commission Decision 2001/423/EC mention that: "the highest level of detail in which data may be published or disseminated is the level of port to and from maritime coastal area. The Commission may however publish at more aggregate level if the quality and/or completeness of information are not appropriate in such detail."
8.1. Release calendar
Statistics of Port Traffic statistics for quarters one, two and three are published four months after the reference period. Quarter four and annual publication is published five months after the reference period.
Release dates are publicly available in the release calendar of the CSO Ireland.
Since release dates are planned sometimes far in advance, changes of dates might occur. Therefore, the release calendar is updated continually.
8.2. Release calendar access
The release calendar is publicly available on the website of the CSO Ireland.
8.3. Release policy - user access
Data is available to all users free of charge. The quarterly and annual publications are published on the CSO website: Statistics of Port Traffic releases.
On the release date, maritime statistics are available to all users at the same time.
National:
Quarterly national maritime transport statistics are published within 4 months after the reference period and annual maritime transport statistics within 5 months after the reference period.
Eurostat:
Quarterly maritime transport statistics are published within 10 months after the reference period and annual maritime transport statistics within 16 months after the reference period.
Maritime statistical data is also published annually as a chapter within the Transport Hub.
10.6. Documentation on methodology
A Standard-documentation with Meta information (Definitions, comments, methods, quality) on Maritime Transport Statistics is available at national level.
10.7. Quality management - documentation
Standard documentation with Meta information (Definitions, comments, methods, quality) on Sea Transport Statistics is available at national level - Maritime statistics methodology.
11.1. Quality assurance
The system follows as far as possible the European Statistics Code of practice and Quality Assurance Framework of the European Statistical System, more precisely Principle 4: Commitment to Quality: Quality policy is defined and made available to the public. An organisational structure and tools are in place to deal with quality management. There are procedures in place to plan, monitor and improve the quality of the statistical processes.
Procedures based on quality reporting are in place to internally monitor product quality. Results are analysed regularly and improving actions are undertaken, if needed (for example after obtaining annual summary results and mirror checks reports from Eurostat). There is a regular and thorough review of the key statistical outputs. Moreover, in the framework of Statistics the CSO has introduced standard quality reports (standard-documentation) to be produced and kept up-to-date for all statistics. The reports are based on the ESS definition of quality in statistics and follow the European standard quality report and provide users with information about the underlying concepts, definitions, methods used and the quality of the statistics (meta-information) in a standardised format.
11.2. Quality management - assessment
Data quality can be assessed as high. There is a set of validation rules and quality checks put in place, which detect various types of issues. In case of any issues detected, the data providers are contacted to provide explanations or/and revise the data accordingly. Checks for the consistency over times are prepared and reviewed. Annually, Eurostat provides a data quality report with a summary of the main findings affecting quality as well as showing the solution adopted and the materiality of the existing differences. Mirror checks and checks for the consistency over times are prepared as well. We have excellent cooperation with the relevant ports. Timeliness and punctuality are very good. Revisions are rare.
12.1. Relevance - User Needs
The key users of maritime transport statistics collected are:
Department of Transport, Eurostat, Universities and research institutions and the general public.
Users involved in the maritime industry (ports, Irish Maritime Development Office (IMDO) etc.)
Data on ships and cargo, routes and trade, and passengers provides an important basis for decision making of politics, society and economy in the context of the development and promotion of transport projects.
12.2. Relevance - User Satisfaction
There was no user survey specially carried out on maritime transport statistics data so far but direct feedback from main users like the Department of Transport universities etc. highlights a good level of satisfaction regarding data coverage and availability.
12.3. Completeness
The collection of data on maritime transport statistics is carried out in accordance with the provisions of Directive 2009/42/EC.
13.1. Accuracy - overall
Overall accuracy of the maritime transport statistics data is good. The processing with checks carried out before transmitting data to Eurostat provides a high accuracy of the data.
13.2. Sampling error
Not applicable for maritime transport data collection.
13.3. Non-sampling error
By working closely with the relevant ports, the various checks and the legal obligation to cooperate and report the data, misclassifications, etc. can be excluded. Moreover, the correctness of the data is of great importance for the ports. The use of the classification lists provided by Eurostat prevents a misclassification of partner ports.
14.1. Timeliness
Quarterly data should be transmitted by Member States to Eurostat within five months of the end of the period of observation; annual data within eight months. The Commission (Eurostat) shall disseminate appropriate statistical data with a periodicity comparable to that of the results transmitted (Directive 2009/42/EC).
14.2. Punctuality
All the statistics required by the provisions of the Directive 2009/42/EC are usually available 1 month before the deadline date.
15.1. Comparability - geographical
There are no problems of comparability for maritime transport data collection with a very high data comparability across countries due to the common legal basis. Comparisons of the data regarding ships, cargo etc. declared by partner reporting ports (so-called mirror checks) by Eurostat allow further the detection of possible inconsistencies which can be corrected if possible.
15.2. Comparability - over time
As from 1995 the statistics on maritime transport are comparable over time, as they are collected following fully the provisions of the legal act - Directive 2009/42/EC. Time series checks are regularly made to detect inconsistencies in the data.
Time series breaks occur in case of port being closed temporarily or permanently or in case a port does not exceed the minimum threshold.
15.3. Coherence - cross domain
Comparisons with other transport statistics are only partially and to a limited extent possible with regard to maritime, since data are currently not available or are not collected at the same level of detail, and also different methods and underlying objectives.
When comparing transported freight with foreign trade statistics, it must be kept in mind that foreign trade statistics exchange goods and their value between individuals, while maritime statistics show the performance of the transport mode sea.
15.4. Coherence - internal
Data collected and sent to Eurostat is consistent.
The burden and costs on the ports is not fully known but is reduced as much as is possible by the CSO.
17.1. Data revision - policy
Maritime statistics are revised if required and this is following a revised report received from the ports.
17.2. Data revision - practice
See 17.1
18.1. Source data
The data is sourced from the ports operating in the Republic of Ireland
18.2. Frequency of data collection
Data is collected quarterly from the main ports and annually from the smaller ports.
18.3. Data collection
Data is collected and processed as per Eurostat regulations.
18.4. Data validation
Data checks are carried out and any errors that cannot be explained are queried with the relevant ports.
18.5. Data compilation
Data is processed and compiled using various files from Eurostat with regard to partner ports etc. Data is sent to Eurostat via eDamis when finalised.
18.6. Adjustment
Not applicable.
No comments
Maritime transport data refer to gross weight of goods (in tonnes), passenger movements (in number of passengers) as well as for vessel traffic (in number of vessels and in gross tonnage of vessels).
Data files are received quarterly from the responding ports and organisations responsible for maritime data.
Port -A place having facilities for merchant ships to moor and to load and/or unload cargo or to disembark and/or embark passengers to or from vessels, usually directly to a pier. Statistical Port -A statistical port consists of one or more ports, normally controlled by a single port authority, which can record ship, passenger and cargo movements. Reporting Port-A statistical port for which statistics of inward and outward maritime transport flows are compiled. Main port -A main port is a statistical port which has annual movements of no less than 200 000 passengers or recording more than one million tonnes of cargo. For ports selected on the basis of only one of these cargo or passenger criteria, detailed statistics are required only for that transport. Maritime coastal area (MCA) -A maritime coastal area is defined as a contiguous stretch of coastline, together with islands offshore. Within a country, an MCA is defined either in terms of one or more ranges of ports along its coastline, or in terms of the latitude and longitude of one or more sets of extremities of the coastal area. Riverbanks can be included. Normally the coastline of each country is allocated to a single maritime coastal area and the coastlines of more than one country may form a single maritime coastal area. There are some exceptions. For example, the USA is separated into a number of maritime coastal areas to cover its overall coastline. For some countries, two separate stretches of coastline may be counted as one maritime coastal area, as, for example, the Atlantic and Pacific coastlines of Mexico. Carriage of goods and passengers by sea -The movement of goods and passengers using seagoing vessels, on voyage which are undertaken wholly or partly by sea. The scope of the Maritime Directive 2009/42/EC also includes goods:
Shipped to offshore installations;
Reclaimed from seabed and unloaded in ports.
Bunkers and stores supplied to vessels shall be excluded from the scope.
Seagoing vessel -Floating marine structure with one or more surface displacement hulls. In the context of the Directive, sea-going vessels are vessels other than those which navigate exclusively in inland waters or in waters within, or closely adjacent to, sheltered waters or areas where port regulations apply. Nationality of registration of seagoing vessel (Flag state) -Every ship is entered in a registry (i.e. list) of ships. Registries are maintained by many countries, each having a set of rules regarding safety procedures, inspection schedules, manning numbers and nationalities for crew and officers, training requirements, etc. Ship-owners select which registry to use based on the balance between the relative cost implications of the rules of each registry and possible penalties from insurance assessments dependent on these rules. Type of cargo- The type of cargo classification, set according to the UNECE - Codes for types of cargo, packages and packaging materials, Recommendation 21, Geneva, March 1986, describes how the goods are being transported in terms of the vessels being used and the port facilities required to handle them. It is therefore very different from the categories of goods classification. Freight container-Special box to carry freight, strengthened and stackable and allowing horizontal or vertical transfers.
Swap bodies are excluded. Although without internal volume flats used in maritime transport should be considered to be a special type of container and therefore are included here. For a fuller description, reference should be made to ISO 668 and 1496.The related term "container cargo" refers to containers, with or without cargo, which are lifted on or off the vessels which carry them by sea.
Ro-Ro unit- This means wheeled equipment for carrying cargo, such as a truck, trailer or semi-trailer, which can be driven or towed onto a vessel. Port or ships' trailers are included in this definition. Classifications should follow United Nations ECE Recommendation No 21 'Codes for types of cargo, packages and packaging materials'. Live animals on the hoof are included. Vehicles being transported as cargo as opposed to a means of transport for freight are recorded in the separate headings of the Ro-Ro cargo classification, when they are rolled on or rolled off a vessel on their own wheels. Ro-Ro cargo -This means goods, whether or not in containers, on Ro-Ro units, and Ro-Ro units, which are rolled on and off the vessels, which carry them by sea. Gross weight of goods -The gross weight of each consignment is the weight of the actual goods together with the immediate packaging in which they are being transported from origin to destination, but excluding the tare weight of containers or Ro-Ro units (e.g. containers, swap bodies and pallets containing goods as well as road goods vehicles, wagons or barges carried on the vessel). This measure of quantity is different from that used in trade statistics, namely the net weight of goods and different from statistics collected on other transport modes where the tare weight is included. Where goods are transported in a road goods vehicle, in a container, or other intermodal transport unit, the gross weight of the goods does not include the tare weight of the transport unit. Gross tonnage -This means the measure of the overall size of a ship determined in accordance with the provisions of the International Convention on Tonnage Measurement of Ships, 1969. Passenger Any person who makes a sea journey on a merchant ship. Service staff assigned to merchant ships is not regarded as passengers. Non-fare paying crewmembers travelling but not assigned and infants in arms are excluded. Cruise passenger -This means a sea passenger making a sea journey on a cruise ship. Passengers on day excursions are excluded. Cruise ship -This means a passenger ship intended to provide passengers with a full tourist experience. All passengers have cabins. Facilities for entertainment aboard are included. Ships operating normal ferry services are excluded, even if some passengers treat the service as a cruise. In addition, cargo-carrying vessels able to carry a very limited number of passengers with their own cabins are also excluded. Ships intended solely for day excursions are also excluded. Cruise passenger excursion -This means a short visit by a cruise passenger to a tourist attraction associated with a port while retaining a cabin on board.
The data used in the domain are collected at port level.
Detailed data are provided for ports handling more than one million tonnes of goods or recording more than 200 000 passenger movements annually (Main ports). The other ports are required to provide summary data. However, detailed data may be included also for minor ports on a voluntary basis.
Maritime ports located in the Republic of Ireland
Quarters for datasets A1, A2, C1, C2, D1, F1 and F2. Whole calendar years for datasets A3, B1 and E1.
Reference period 2021
Overall accuracy of the maritime transport statistics data is good. The processing with checks carried out before transmitting data to Eurostat provides a high accuracy of the data.
The units used depend on the variables collected within each data set and are: gross weight of goods expressed in thousands of tonnes; number of passengers in thousands, number of vessels.
TEUs: Twenty feet equivalent units, expressed in units or in thousands depending on the table. TEU calculation coefficients:
20-ft freight units (1 TEU).
40-ft freight units (2 TEU).
Freight units over 20-ft and under 40-ft in length (1.5 TEU).
Freight units over 40-ft long (2.25 TEU).
Data is processed and compiled using various files from Eurostat with regard to partner ports etc. Data is sent to Eurostat via eDamis when finalised.
The data is sourced from the ports operating in the Republic of Ireland
National:
Quarterly national maritime transport statistics are published within 4 months after the reference period and annual maritime transport statistics within 5 months after the reference period.
Eurostat:
Quarterly maritime transport statistics are published within 10 months after the reference period and annual maritime transport statistics within 16 months after the reference period.
Quarterly data should be transmitted by Member States to Eurostat within five months of the end of the period of observation; annual data within eight months. The Commission (Eurostat) shall disseminate appropriate statistical data with a periodicity comparable to that of the results transmitted (Directive 2009/42/EC).
There are no problems of comparability for maritime transport data collection with a very high data comparability across countries due to the common legal basis. Comparisons of the data regarding ships, cargo etc. declared by partner reporting ports (so-called mirror checks) by Eurostat allow further the detection of possible inconsistencies which can be corrected if possible.
As from 1995 the statistics on maritime transport are comparable over time, as they are collected following fully the provisions of the legal act - Directive 2009/42/EC. Time series checks are regularly made to detect inconsistencies in the data.
Time series breaks occur in case of port being closed temporarily or permanently or in case a port does not exceed the minimum threshold.
