What is a UN/LOCODE?
· 3 min read
In short
A UN/LOCODE (United Nations Code for Trade and Transport Locations) is a five-character code for a port or other place used in trade: two letters for the country, from ISO 3166, and three characters for the place. NLRTM is Rotterdam in the Netherlands, SGSIN is Singapore, USLAX is Los Angeles. The code list is maintained by the UN Economic Commission for Europe (UNECE) under its Recommendation 16, and it is how ships are meant to write their destination in AIS.
How a code is built
| Code | Country part | Place part | Place |
|---|---|---|---|
| NLRTM | NL (Netherlands) | RTM | Rotterdam |
| SGSIN | SG (Singapore) | SIN | Singapore |
| DEHAM | DE (Germany) | HAM | Hamburg |
| USLAX | US (United States) | LAX | Los Angeles |
The first two letters are the ISO 3166-1 alpha-2 country code. The last three identify the place within the country and are letters where possible; when digits are needed, only 2 to 9 are used, so they cannot be confused with the letters O and I. The place part often echoes an older code (LAX is also Los Angeles’s airport code), but it is assigned separately and need not match.
Each entry also carries a function classifier saying what the place is used for: 1 for a port, 2 for rail, 3 for road, 4 for an airport, 5 for a postal exchange, 6 for multimodal functions such as inland container depots, and 7 for fixed transport installations such as oil platforms. A place with several functions lists them all. Inland waterway ports also use 1.
Who maintains it
UNECE’s Centre for Trade Facilitation and Electronic Business (UN/CEFACT) maintains the list and publishes new releases regularly, based on requests from national focal points and users. It is used on bills of lading, in customs and port systems, in electronic data interchange and by shipping lines’ schedules, so the same port has the same code in every document.
UN/LOCODE in AIS
The destination a ship broadcasts over AIS is 20 characters of text typed by the crew. IMO resolution A.1106(29) recommends using UN/LOCODE for it, and using the same field for both the port of departure and the next port. In practice crews write codes, names, abbreviations or instructions such as “FOR ORDERS”, which is why a tracker has to interpret the destination and why Voydar shows it as reported.
Voydar’s own port pages are keyed by UN/LOCODE: every port URL starts with the code, so /port/nlrtm-rotterdam is Rotterdam whatever the name is spelled as. Large port complexes can have several codes for different terminals or areas; Voydar shows them on the main port’s page.
UN/LOCODE on Voydar
Live from Voydar| Port | UN/LOCODE | Country part | Place part |
|---|---|---|---|
| Rotterdam | NLRTM | NL (Netherlands) | RTM |
| Singapore | SGSIN | SG (Singapore) | SIN |
| Hamburg | DEHAM | DE (Germany) | HAM |
| Antwerpen | BEANR | BE (Belgium) | ANR |
| Busan | KRPUS | KR (South Korea) | PUS |
| Hong Kong | HKHKG | HK (Hong Kong) | HKG |
| Los Angeles | USLAX | US (United States) | LAX |
| Piraeus | GRPIR | GR (Greece) | PIR |
| Kiel | DEKEL | DE (Germany) | KEL |
From code to port call
A code identifies a place; a port call is a ship actually being there. Voydar detects port calls from AIS positions rather than from the typed destination, because positions are measured and destinations are not. How that works is explained in how ship tracking works. Browse ports by country to see recent arrivals and departures.
Questions and answers
- What is the UN/LOCODE for Rotterdam?
- NLRTM: NL for the Netherlands and RTM for Rotterdam.
- Is a UN/LOCODE the same as an airport code?
- No. Airport codes are assigned by IATA and ICAO. Some UN/LOCODE place parts happen to match an IATA code, but the systems are separate and cover different places.
- Why does a ship’s destination not look like a UN/LOCODE?
- Because the crew types it by hand. IMO guidelines recommend UN/LOCODE, but free text, port names and abbreviations are common.
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Sources
Primary sources for the facts in this guide. Figures labelled as Voydar data come from Voydar’s own records, with their method stated next to them.
- UNECE: UN/LOCODE
- UNECE Recommendation 16: UN/LOCODE, code for trade and transport locations
- UNECE: UN/LOCODE column description (function classifiers)
- IMO resolution A.1106(29): Revised guidelines for the onboard operational use of AIS
Published Sep 28, 2026 · For information only. Not for navigation, and not a substitute for the official sources cited.