To enter and depart Peru, you must have a valid U.S. passport. For short-term visits of up to 183 days, a visa can be issued free of charge at the point of entry.
Proof of onward travel, may be required by Migraciones (Immigration) authorities. Make sure to have your date and place of entry stamped in your passport, otherwise you will have issues getting out of Peru. Peruvian immigration procedures are complex for minors traveling without one or both parents/legal guardians. Consent forms are strongly recommended for minors traveling with only one parent/legal guardian. For minors staying as a tourist for more than 183 days, a Permiso Notarial de Viaje is required.