How to get SIM cards in Chile, a guide to find the best prepaid SIM cards
These are the main Telco providers in Chile:
Movistar
Entel
Claro
WOM
Entel and Movistar are Chile's top telco providers with Movistar having the highest coverage while Entel has the highest data speed, which makes Entel the best telco provider but only in urban centers since it has low coverage in non-urban areas.
Registration
When you first purchase your SIM card no registration is necessary. However, after 30 days you have to register your SIM card for anti-theft purposes.
Documents needed for SIM card registration are:
Your phone's IMEI number.
Proof of entry into Chile- Tourist visa card or passport with entry stamp.
A copy of your passport
Always make sure your seller activates your RUT number after SIM card purchase otherwise you won't be able to use it.
Where to purchase SIM cards in Chile.
You can get prepaid SIM cards at the top floor in Santiago international airport just after the check-in and ticketing area. Claro, Entel, and Movistar SIM cards are all available, however, unless you urgently one I advise not to buy SIM cards at the airport since they are slightly expensive here.
You'll find SIM cards at supermarkets and kiosks all over Chile retailing for between CLP2000-3000.
IMPORTANT INFO: I noticed that most SIM card retailers in Chile don't sell prepaid SIM cards and you really have to search around before finding sellers who have such services, telco providers here sell set plans instead of using prepaid SIM cards.