Yes, all international travel require a passport (must be valid for 6 months from the date of travel). Some destinations require a Visa (especially for Non-US citizens) and you will be notified of the tours that require a visa, along with the information needed to obtain one when necessary.
**NOTE: It is always best practice to travel with a Passport at all times. It is your responsibility to insure that you have the proper documentation to participate in our tours. Some domestic travel may also require additional identification. Please refer to https://travel.state.gov for further information.