Before your trip, it's best to exchange money at your bank or credit union, which likely offers better rates and fewer and/or lower fees. Your bank or credit union may buy back leftover foreign currency in exchange for dollars when you return.
Bank. You can buy euros with dollars at major banks like Wells Fargo and Bank of America. You will need to be a bank customer already and can order euros online easily. ...
Foreign Currency Exchange. Money changers can be the cheapest way to buy euros. ...
Airport. Yes, you can buy currency at the airport.
But if you pay in euros, you'll get a rotten exchange rate. Ideally, if you're in a non-euro country for more than a few hours, head to the ATM and use local currency instead. Use your credit card to get cash only in emergencies.