Thus, for example to call a local number within Buenos Aires, one should dial 1234–5678; within Mar del Plata, 123-4567 and within Villa Carlos Paz, 12–3456.
In March 2011, the National Communications Commission announced changes to be carried out in 21 local areas throughout the country.
As explained before, area codes can have 2, 3 or 4 digits and must be dialed before the local subscriber's phone number.
Calling a mobile phone locally requires dialing 15, followed by the subscriber's number.
For example, to call a Mar del Plata mobile from Buenos Aires, the dialing pattern is 0 223 15 xxx-xxxx, where 0 is the trunk code, 223 is the Mar del Plata area code, 15 is the mobile prefix, followed by the seven-digit subscriber number.
In 2000 President Fernando De La Rúa signed a decree[5] deregulating the telephone service in Argentina, thus allowing number portability to be implemented.
In December 2011, Argentine authorities postponed number portability once again—allegedly due to lobbying from operators—until March 2012.
[6] The intention is that users of landline and mobile telephones in Argentina will be able to switch providers while keeping their phone number, so long as they remain in the same subscriber local area.
For example, to call mobile number (223) 15 123–4567 (in Mar del Plata) from outside Argentina, the dialling sequence is: +54 9 223 123–4567.
For example, if the mobile number in Argentina is (11) 15 1234–5678, a voice call from abroad would be dialled as +54 9 11 1234 5678, but a text message would require +54 11 1234 5678, with +54 9 11 1234 5678 usually being invalid.
Although Argentina claims sovereignty over the Falkland Islands, international dialling using the 00 prefix and the country code 500 is required.
Prefixes allocated as of 2013[update] include: The format for public utility service phone numbers is mostly 1xx.