Although Chile and Argentina do not require visas for US travelers, both countries require travelers holding US passports to pay a $160 reciprocity fee in order to enter. This amount is equal to the amount that Argentines and Chileans are required to pay for visas to enter the United States. To streamline the immigration process, new procedures will take effect at the end of the year in Argentina. It’s important to be aware of these changes since travelers who fail to follow the new procedures could find themselves stranded at the airport unable to enter country.
Starting December 28, 2012, US visitors to Argentina arriving on flights into either of the two airports in Buenos Aires (Ministro Pistarini International Airport, more commonly known as Ezeiza, and Aeroparque Jorge Newbery) must pay the reciprocity fee online in advance. Beginning January 7, 2013, online prepayment of the reciprocity fee will also be required for travelers crossing into Argentina by land and sea (although cruise ship passengers will be exempted from the fee until June 30, 2013). The receipt for prepayment must be shown upon arrival in Argentina.
The website for payment is: Migraciones
For Chile, the reciprocity fee is currently only required of travelers arriving through Santiago International Airport. Payments are made at the airport, with payment either by US cash or by credit card. In other words, if you enter Chile by land, sea, or through another airport, you do not have to pay the fee.
For both Argentina and Chile, the reciprocity fee is good for multiple entries over a period of 10 years. If your passport expires you may be able to avoid paying additional fees on return visits within the 10-year period by showing your old passport with the valid proof of payment. Check with the appropriate embassy for the most recent rules about carrying over reciprocity fees to a new passport.
Travelers from Canada and Australia are also subject to reciprocity fees, although the amounts and validity periods vary.