Foreign currency can be changed at Sea-Tac airport or in downtown Seattle [1] exchange bureaus. Travelers checks are the safest way to carry money, but buy them from a well-known U.S. company such as American Express, Bank of America, or Visa. They are accepted without charge in most stores and businesses. It’s not a good idea to travel with travelers checks in non-U.S. currency, since they are only accepted at a few banks and are a time-consuming hassle.
Automated teller machines are ubiquitous in Washington state. Find an up-to-date listing of Cirrus system ATMs at 800/424-7787 or www.mastercard.com; for the Plus system, 800/843-7587 or www.visa.com/atms [2].
The major credit cards—especially Visa and Master Card—are accepted virtually everywhere. For many travelers this is the easiest way to access funds while traveling.
Links:
[1] http://www.moon.com/destinations/washington/seattle
[2] http://www.visa.com/atms