In general, it is advisable to carry a small amount of cash in USD or Costa Rican Colones.With VISA, MASTERCARD, and AMERICAN EXPRESS you can pay almost everywhere, with DINER’S CLUB unfortunately not. In general, it is advisable to carry a small amount of cash in US$ (small notes 1, 5, 10, 20) or Colones.
Traveler’s checks can only be cashed by banks. This usually takes some time and it will be charged a fee (1-5%).
It is mandatory to show your passport when changing money at banks, changing traveler’s checks, paying with credit card, and usually also when paying with US$ notes (bank notes higher than US$ 20.-- are often accepted by banks only).