The telephone system in Colombia is modern and works well for both domestic and international calls. Landlines are operated by different companies in different cities many of which were once state entities that have been privatized.
Public telephones exist in cities and large towns, but they are few and far between, and most are out of order. In their place you'll see shops, kiosks and street vendors selling 'minutos' or phone minutes on a bunch of mobile handsets. These vendors purchase prepaid minutes in bulk, and it is always cheaper to make calls with them than to use credit on your own handset. For this reason many Colombians use their handsets to receive calls only and use street vendors when they need to make calls. Rates oscillate between COP$150 and COP$400 a minute to call anywhere in the country.
Internet cafes almost always have a few cabinas (telephone booths) where you can make both local and international calls for around a few hundred pesos a minute.
It is possible to call direct to just about anywhere in Colombia from any phone, but to dial a landline from a cell (mobile) phone, you'll need to prefix the number with 03 + area code. Many landlines are barred from making calls to cell phones.
Landline phone numbers are seven digits countrywide, while cell-phone numbers are 10 digits. Area codes are single digits.
Colombia's country code is 57. If you are dialing a Colombian landline number from abroad, add the single digit area code and then dial the local number. Cell numbers have no area code and should be dialed directly after the country code.
Cell (mobile) phone and mobile data coverage is excellent. Most unlocked cell phones will work with a local SIM card.
Colombians love their cell phones, and in urban areas almost everyone has at least one. The three major providers are Claro (www.claro.com.co), Movistar (www.movistar.co) and Tigo (www.tigo.com.co). Claro has the best nationwide coverage, and is the most useful to the traveler. Cell phones are cheap, and many travelers end up purchasing one – a basic, no-frills handset will set you back around COP$130,000.
Alternatively you could bring your own cell phone from home and buy a Colombian SIM card which usually costs around COP$5000. You will need to take ID to buy a SIM from one of the companies; you can also buy them from third parties but eventually you'll need to register with the company or risk having your handset blocked.
Colombian cell-phone companies do not charge you to receive calls, only to make them.