At Quito Airport and Guayaquil Airport, you can exchange money in various currencies but this is pretty expensive. There are very few locations in the rest of Ecuador where you can exchange American dollars for other currencies than the euro. Your best bet for exchanging dollars for euros (or vice versa) are the main offices of Banco Guayaquil in larger cities. When you exchange money you always have to show your passport or id-card. Special money exchange venues like in many other countries hardly exist in Ecuador.
Safety measures at banks
Bank robberies and especially the robberies of bank clients are a problem in Ecuador. For this reason, all banks have one or more guards. As a visitor to a bank office, you're not allowed to use your mobile phone inside banks because mobile phones can be used to inform robbers
If you want to bring a large amount of money to or from a bank, you can call 911 to arrange a free escort by the police.
See our Ecuador Crime and Safety Guide for more recommendations.