You can get a prepaid Movistar / Claro / Personal SIM card for a few pesos / free at phone shops, all you pay is about ARS20 (about USD5) for your initial credits. Inserting the SIM card into your unlocked mobile phone should work, although to register the SIM you might have to enter your passport (or any 9 digit) number - you then have your personal Argentinian phone number, which is very useful to keep in touch with other travellers, either by calling or by writing text messages. Calls cost around ARS1 per minute. Still, having to register the SIM card is extremely rare.
Receiving calls is usually free, except for international calls, and some cross network / inter-city calls - hence buying a SIM card purely to keep in touch with people overseas may not be worth it.
To reload you can buy small cards with secret numbers at many kiosks, but the easiest way is just to ask for "Recarga Virtual" and tell the shop assistant your Phone number and company, and the amount of pesos you want to recharge.
Not related to mobile phones, there are similar cards with credits for international calls. You get them at so called locutorios, where you can also use the phone booths. You dial a free number to connect to the service, then your secret number for the credits, and then the international phone number you want to call. Using these cards, a one-hour call to Europe will cost about 10 Pesos (3 US-Dollars). Don't call without such cards or even from your hotel - it will be way more expensive.
The phone numbering plan in Argentina is hopelessly complicated for foreigners. Do check out the Wikipedia article about it to find out more.
- Directory Listing (The White Pages): 110
- International Operator: 000
- National Operator: 19
- Collect National Calls: 19 from regular phones, *19 from public phones
- Mobile phone numbers start with 15 or 11
- Regional code for Buenos Aires: 011
Other useful phone numbers include:
- Official Time: 113
- Consumer Advocacy: +54 11 5382-6216 or 6217
All 2 and 3-digit numbers are free, except the official time service (113).
All 0800 numbers are toll-free numbers, except if you call from a mobile phone.
Long distance calls from Argentina: You may use calling card, ARS0.18/min or ARS0.59/min for calling from Argentina to USA.
Most cafés and restaurants offer free Wi-Fi with an advertisement in their windows. All you need to do is buy a coffee and ask for the password. Public WiFi is also very common in Buenos Aires with great speeds. The network name will be BA Wifi