Short codes are not location based, but are carrier based. So for users in other countries who are using one of the major US telecoms (such as T-Mobile or Verizon) the short code will work, but if they are on a smaller, local to that country, carrier, it will likely not work. Similarly, if a US Verizon customer travels to Europe, it is expected that the short code will still work for them. Here is a list of all of the carriers currently supported on US short codes:
