Yes, Lawful Permanent Residents (green card holders) are allowed to travel internationally, but they must follow specific "high-fidelity" rules to protect their status. To re-enter the U.S., you must present your valid Green Card (Form I-551). While the U.S. does not require a passport for your return, the country you are visiting almost certainly will, so you must maintain a valid passport from your country of citizenship. For trips shorter than six months, there is usually no issue. However, if you stay outside the U.S. for more than six months but less than a year, you may face "rebuttable presumption" that you have abandoned your residence and will be questioned by CBP. For any trip planned to last longer than one year, you must apply for a Re-entry Permit (Form I-131) before leaving the U.S. to avoid losing your status. In 2026, it is critical for green card holders to track their travel history accurately, as lengthy absences can delay or disqualify them from applying for U.S. citizenship (naturalization) later.