As per the basic rule of Permanent residency (Green Card) travel for over 6 months may break the continuous residence requirement and you may loose your permanent residency status.

If you are a Permanent resident( Green card holder) and planning to travel outside of USA, and remain outside for more then 6 months, you must get a Re-entry permit to keep your Green Card alive and prevent any issue to re-enter into USA. Re-entry permits are generally valid for two years from the date of issuance of the re-entry permit.

A re-entry permit can help prevent two types of problems:
(1) Your Permanent Resident Card becoming technically invalid for re-entry into the United States (U.S.), if you are absent from the U.S. for 1 year or more.
(2) Your U.S. permanent residence being considered as abandoned for absences shorter than 1 year, if you take up residence in another country.
A re-entry permit establishes a presumption that you did not abandon status, and it allows you to apply for admission to the U.S. after traveling abroad for up to 2 years, without having to obtain a returning resident visa. Re-entry permits are normally valid for 2 years from the date of issuance. You may also want to get a re-entry permit if you plan

How to get a re-entry permit?

If you want to get a re-entry permit, file Form I-131, Application for Travel Document, complete with supporting documentation, photos and applicable fees.

This form can be downloaded from our Forms and Fees page of USCIS website.

You may have to provide the following document along with the application.

  • A copy of the alien registration receipt card; or
  • If he has not yet received his alien registration receipt card, a copy of the biographic page of his passport and the page of his passport indicating initial admission as a permanent resident, or other evidence that the alien is a permanent resident; or
  • A copy of the approval notice of a separate application for replacement of the alien registration receipt card or temporary evidence of permanent resident status.

The address to send the application is given in the form itself. Send the completed form, fee and other required documents through a registered/certified mail.

You should file this application well in advance of your planned trip.

What will happen if you not apply for a re-entry permit before I travel outside of the U.S. ?

If you are a permanent resident who plans to travel outside of the U.S. for one year or more, it is important that you apply for a re-entry permit before you depart the U.S. If you stay outside of the U.S. for one year or more and did not apply for a re-entry permit before you left, then you may be considered to have abandoned your permanent resident status and may be refused entry into the U.S. if you try to return. If you are in this situation, contact the U.S. Consulate about a returning resident visa. Can I apply for the re-entry permit and then leave, even though I don't have the re-entry permit in my possession yet? U.S. immigration law does not require that you have the re-entry document in your possession when you depart, but it does require that you apply for the permit before you leave the U.S. We may be able to send your re-entry permit to the U.S. Consulate or Embassy in the country you plan on visiting, but you'll need to specifically request this when you file your I-131. If you choose this option, you should contact the U.S. Consulate or Embassy in the country you plan on visiting when you arrive, to let them know how to contact you while you are in that country. The US Consulates or Embassy may then contact you if your application is approved and your permit has arrived there.

It is advisable to plan your trip in advance and get this document before traveling for peace of mind.