Citizens of the United States traveling to Guatemala  will need a U.S. passport valid for at least six months beyond their intended length of stay and ticket documents for onward or return travel. Stays of up to 90 days are permitted without a visa. The United States now requires passports as the sole travel document for all travelers returning to the United States by air.
Requirements for other countries, including Australia, Canada, The European Union, Israel, Japan, New Zealand, and Switzerland include a passport valid for at least three months beyond their intended length of stay and ticket documents for onward or return travel. Entry is limited to 30 days. Extensions are allowed by going through the local Migración (Immigration) office.
Foreigners are required to carry their passport (or a clear photocopy) with them at all times. If you are driving a rental car and happen to be stopped, the police officer will ask for your passport in addition to your driver’s license.
In June 2006, Guatemala entered into an agreement with El Salvador, Honduras, and Nicaragua known as the CA-4 Border Control Agreement. Under its terms, citizens of these four countries may travel freely across each other’s land borders without completing entry and exit formalities at Immigration checkpoints. United States citizens and other eligible foreign nationals who legally enter any of the four member countries may also travel within the CA-4 without obtaining additional visas or tourist entry permits for the other three countries. Immigration officials at the first port of entry determine the length of stay, up to a maximum of 90 days. Foreign tourists who wish to remain in the four-country region beyond the length of stay initially granted for their visit will need to request a one-time extension from local Immigration authorities or travel to a country outside the CA-4 region and then reenter.
For visa extensions, head to the Departamento de Extranjería (7a Avenida 1-17 Zona 4, INGUAT Building, Guatemala City, tel. 2361-8476, 8 a.m.–2 p.m. Mon.–Fri.). You’ll need to show evidence of financial solvency as well as an onward ticket.