Street phones require coins or tarjetas telefónicas (magnetic phone cards available at many kioskos, or small markets). You’ll only be able to speak for a limited time before you get cut off, so make sure you're carrying enough credit.
Toll-free numbers in BA have '0800' before a seven-digit number.
It's best to bring your own factory unlocked tri- or quad-band GSM cell phone, then buy an inexpensive local SIM card and credits (or cargo virtual) as needed.
Bringing Your Own Phone
Both SIM cards (known as 'chips' in Argentina) and credits can be bought at many kioskos or locutorios (small telephone offices); look for the ‘recarga facil’ signs. Many Argentines use this system with their cell phones, and you can buy SIM cards with data for wi-fi access as well. Phone-unlocking services are available; ask around.
You can also buy cell phones that use SIM cards; these usually include some credits for your first batch of calls.
If you plan to travel with an iPhone or other smartphone, prepare yourself – you may need to purchase an international plan to avoid being hit by a huge bill for roaming costs. On the other hand, it’s possible to call internationally for free or very cheaply using a VoIP (Voice over Internet Protocol) system such as Skype. This is a constantly changing field, so do some research before you travel.
Calling Mobile Phones
Cell-phone numbers in Argentina are always preceded by ’15.' If you’re calling a cellular phone number from a landline, you’ll have to dial 15 first. But if you’re calling a cell phone from another cell phone, you don’t need to dial 15 (at least within the same area code).
When calling cell phones from outside Argentina, dial your country’s international access code, then 54 9 11 and then the eight-digit number, leaving out the 15.
The Buenos Aires area code is 011. You will need to dial this when calling BA from outside the city, but you don't need to dial it when calling from within BA.
Telephone calling cards are sold at nearly all kioskos and make domestic and international calls far cheaper than calling direct. However, they must be used from a fixed line such as a home or hotel telephone (provided you can dial outside the hotel). They cannot be used at most pay phones.
Some locutorios allow you to use them, and although they levy a surcharge, the call is still cheaper than dialing direct. When purchasing one, tell the clerk the country you will be calling so that they give you the right card.
One way to make a local or international phone call is to find a locutorio, a small telephone office with private booths from which you make your calls and then pay at the register. There’s a locutorio on practically every other block in the Center.
When making international calls from locutorios ask about off-peak discount hours, which generally apply after 10pm and on weekends. Making international calls over the internet using Skype is a cheap option; many internet cafes have this system in place.