Even if you have a credit card that has no foreign transaction fees, you’ll often be charged extra for foreign credit card purchases in Chile. This is on top of the fees of roughly 3-5% that credit cards which do charge foreign transaction fees will charge for currency conversion.
Typically your credit card will first be declined, then when you try again, you’ll need to accept a charge of a few hundred or even thousand Chilean pesos to continue the transaction. Some Chilean credit card processors charge these extra fees for some reason - I haven’t seen the fees in any other country, and not all Chilean card processors have them.
But after asking around, I finally found out how gringos can avoid the fees. It turns out American Express cards don’t get charged these fees - I’m guessing either that Amex has worked out some sort of partnership with the payment processors, or maybe they just cover their customer’s fees. Either way, the way to avoid these fees is to get an Amex card with no foreign transaction fees. I got the Amex Gold and I’d recommend it - the annual fee is $250, but you get $240 in monthly credits for GrubHub and Uber, and a few other discounts and benefits that make it worth the fee. Plus, a 60,000 point sign up bonus and good points earnings after that for restaurants, flights and super markets. And if you do choose to sign up, I’d really appreciate it if you’d throw a few miles my way by using this referral link ;).
Hope you enjoy your time in Chile!