FBAR is a calendar-year report. Currently you must file it on or before June 30 of the year after the calendar year you are reporting (for example, an FBAR for 2015 is due by June 30, 2016).
For tax years that begin January 1, 2016, you must file on or before April 15 of the following calendar year (for example, a 2016 FBAR will be due April 15, 2017).
Extensions: You can’t ask for more time to file an FBAR. When the IRS grants a filing extension for a federal tax return, it does not extend the time to file an FBAR with FinCEN. Note: When the new due date goes into effect (April 15th) for tax years beginning January 2016, you will be able to request a six month extension for filing FBAR.
Exception: FinCEN Notice 2014-1 extended the due date for filing FBARs by certain individuals with signature authority over, but no financial interest in, foreign financial accounts of their employer or a closely-related entity, to June 30, 2016. This notice continues the extension granted in Notice 2013-1 (extended to June 30, 2015) to similarly situated individuals.
If you're going to file your own FBAR
File the FBAR electronically through FinCEN’s Bank Secrecy Act (BSA) E-Filing System.
NOTE: Don’t file the FBAR with a federal tax return; you must file it separately as mentioned above.
If someone else is going to file the FBAR on your behalf
If you choose to have a third-party preparer file FBARs on your behalf, you need to fill in and keep a copy of FinCEN Report 114a, Record of Authorization to Electronically File FBARs. You don’t have to submit it with your FBAR, but it must be available to FinCEN or the IRS if requested.