EU (European Union) country codes, ISO 3166-1 alpha-2. (This Gist is from 2012. Please see comments for updates.)

eu_country_codes.rb

# Note: VAT identification numbers for Greece use "EL", not "GR".

COUNTRY_CODES_EU = %w[
  AT BE BG CY CZ DK EE FI FR DE GR HU IE IT
  LV LT LU MT NL PL PT RO SK SI ES SE GB
]

For those getting here are writing JavaScript/TypeScript. Leverage Set for validating EU member nations by country code, eg:

const EU = new Set([
  'AL',
  'AD',
  'AT',
  'AZ',
  'BY',
  'BE',
  'BA',
  'BG',
  'HR',
  'CY',
  'CZ',
  'DK',
  'EE',
  'FI',
  'FR',
  'GE',
  'DE',
  'GR',
  'HU',
  'IS',
  'IE',
  'IT',
  'KZ',
  'XK',
  'LV',
  'LI',
  'LT',
  'LU',
  'MK',
  'MT',
  'MD',
  'MC',
  'ME',
  'NL',
  'NO',
  'PL',
  'PT',
  'RO',
  'RU',
  'SM',
  'RS',
  'SK',
  'SI',
  'ES',
  'SE',
  'CH',
  'TR',
  'UA',
  'GB',
  'VA',
])

const isEU = (code: string): boolean => EU.has(code)

This is the cleanest way to do this. I have seen developers reach for iteration for matches, try not to do this, as a pre-populated Set will suffice nicely and comes at little cost. For some additional helper utils (which might of use to you all) we open sourced a couple little modules, for dealing with i18n aspects that somewhat pertain to this nexus:

Country code to currency code mappings:

• @brixtol/currency-codes

Country code to country name (English) mappings:

• @brixtol/country-names

Hope it helps! Happy coding.

@bigghe @plpepin @panoply the UK (GB) is no longer in the EU, sadly. So your lists are not correct.

The list of EU countries is here courtesy of Eurostat, the "statistical office of the European Union"

Also, note that the European Commission does not always use ISO 3166-1 alpha-2 codes, including at the Eurostat link above. As explained on Wikipedia:

The European Commission generally uses ISO 3166-1 alpha-2 codes with two exceptions: EL (not GR) is used to represent Greece, and UK (not GB) is used to represent the United Kingdom.[10] This notwithstanding, the Official Journal of the European Communities specified that GR and GB be used to represent Greece and United Kingdom respectively.[11] For VAT administration purposes, the European Commission uses EL and GB for Greece and the United Kingdom respectively.

So, depending on your use case, you may need to amend and extend the list of standard ISO 3166-1 alpha-2 codes

@bradydan is it official in UK already? I will have peek on the E.U governing sites. I am aware of the EL reference for Greece (I am Greek) however the vast majority of services feed GR when they are US based, might be worth adding EL in any sense. Wikipedia cannot be trusted nowadays, I will look on the gov counterparts and amend where necessary once I can confirm. Thanks for taking the time to leave your comment fam.

@bradydan The UK adopted GDPR into the law when they left the EU.

I think this is an up to date 2022 list? https://www.defensorum.com/gdpr-countries-list/

I asked and answered this stack overflow question to come up with this list which I believe is up to date for 2022: AT, BE, BG, HR, CY, CZ, DK, EE, FI, FR, DE, EL, HU, IE, IT, LV, LT, LU, MT, NL, PL, PT, RO, SK, SI, ES, SE, UK

What a helpful thread! The list posted by Dan is almost right - UK is no longer part of the EU.

According to the UK government atleast: https://www.gov.uk/eu-eea
According to the canadian governement from 2013 (so needs modification): https://www23.statcan.gc.ca/imdb/p3VD.pl?Function=getVD&TVD=141329
According to the actual EU: https://european-union.europa.eu/easy-read_en

The alpha 2 code for Greece is GR no EL - which AFIK is not a valid Alpha2 code.
The correct list (with Alpha2 codes) would then be:

AT BE BG HR CY CZ DK EE FI FR DE GR HU IE IT LV LT LU MT NL PL PT RO SK SI ES SE

Cheers!

This thread was originally about EU countries, them @mizterp changed the topic to GDPR countries and it (confusingly) became a mixture of both topics.