Country codes

Part 1 has three forms:

ISO publishes the codes through its Online Browsing Platform. ISO adds and changes entries from time to time, so don't hard-code a list you downloaded once.

• GB, not UK. The ISO code for the United Kingdom is GB. Writing "UK" is a common cause of rejected address data, even though the country's name uses it.
• XI for Northern Ireland. This isn't an ISO country code. It's used in EU and UK customs and VAT contexts for Northern Ireland, for example on an EORI or a VAT number under the Windsor Framework.
• EL for Greece, in VAT. The ISO code is GR, but EU VAT numbers use the prefix EL. An EORI starts with the two-letter code of the issuing country, so check the format per system rather than assume.
• EU isn't a country. Origin is usually declared at country level, unless a rule says otherwise. On the US Section 301 schedule, for example, the EU has its own headings.
• Territories have their own codes. Hong Kong (HK), Macao (MO), Puerto Rico (PR) and others are listed separately in ISO 3166-1. The customs treatment doesn't always follow the same line, so check the tariff.

UN/LOCODE is five characters: the two-letter ISO country code, then three for the place. A customs or carrier system may also have its own port codes, such as the US Schedule D codes, so a LOCODE doesn't always fit.

Use the code for the country of origin on your commercial invoice, and keep it separate from the code for the country you shipped from, because the two are often different. In your own systems, store the code as a coded field with validation, and don't accept free text. When you connect to a data feed or a carrier's system, check whether it wants alpha-2 or alpha-3, and map to that: a three-letter code in a two-letter field usually fails at the worst time. For why the origin field matters so much, see country of origin.