If you are a U.S. citizen or resident, and both your tax home and your abode are outside the United States and Puerto Rico on the regular due date of your return, you are automatically granted an extension (usually to June 15) to file your return and pay any tax due. You do not have to file a special form to receive this extension. You must, however, attach a statement to your tax return when you file it showing that you are eligible for this automatic extension.
It may benefit you to file for an additional extension of time to file. You may benefit if, on the due date for filing, you have not yet met either the bona fide residence test or the physical presence test, but you expect to qualify after the automatic extension discussed above and have no tax liability. To file for an additional extension, send Form 2350, Application for Extension of Time To File U.S. Individual Income Tax Return, to the Internal Revenue Service Center in Philadelphia or to your local IRS representative. Send the form after the close of your tax year but before the end of the first extension. If an extension is granted, it will be to a date after which you expect to meet the time requirements for the bona fide residence or physical presence test. You must attach the approved Form 2350 to your income tax return when you file.