The currency being used by Portugal is the euro. If you have dollars and you are coming for a vacation from the US into Portugal, or if you have pounds from the UK or Swedish krona from Sweden, you could buy euros at your local bank. It is also possible to buy traveler’s checks although I don’t see a lot of people using traveler’s checks these days any more, but they come with a guarantee and protection, so a traveler’s check is a more suitable choice especially for the older generation.
You can also simply use your ATM or cash withdrawal cards in most local ATMs in Europe. Your bank will charge you for doing so. You could withdraw euros at the local ATMs in Portugal and then you will get a bill in the US in dollars with the rates stipulated by the banks.
If you are coming to Portugal for a longer period then we recommend that you use a currency broker because currency brokers can transact millions of dollars, pounds, or whatever currency per day. They would be able to get you a better rate and allow you to get “more euro for your buck”.
(Money clip of Portuguese coin before the euro, pictured.)