Here is my discussion in the current draft for the next revision (due August 2017) of my Federal Tax Procedure Book (note that the footnote numbers are not the ones that will be in the final text)):
The FBAR was historically required to be filed on June 30 for the prior year. In 2015, Congress changed the filing date to April 15 (contemporaneously with the individual income tax return due date for calendar year taxpayers, which can be the next succeeding business day if April 15 falls on a weekend or holiday) with the ability to obtain a 6-month extension to October 15 (also contemporaneous with the extended due date for individual income tax returns and also extended to the next succeeding business day if October 15 falls on a weekend or holiday). n1 Under the current instructions, FinCEN grants an automatic extension from April 15 to October 15; the automatic extension applies without any action on the filer’s part other than not filing by the original due date. n2Some helpful web pages (including the one mentioned in fn. 2 above are:
n1 § 2006(b)(11), the Surface Transportation and Veterans Health Care Choice Improvement Act of 2015 (P.L. 114-41). The effective date of this FBAR filing provision is the filing year 2016 (i.e., the 2016 FBAR is due April 15, 2017 (actually, on the next succeeding business day), subject to the automatic extension to October 15, 2017 noted in the text).
n2 FinCEN web page, titled New Due Date for FBARs (12/16/16), viewed 2/1/17, providing in relevant part after noting the statutory due date of April 15 (emphasis supplied):
To implement the statute with minimal burden to the public and FinCEN, FinCEN will grant filers failing to meet the FBAR annual due date of April 15 an automatic extension to October 15 each year. Accordingly, specific requests for this extension are not required. (Please note: The due date for FBAR filings for foreign financial accounts maintained during calendar year 2016 is April 18, 2017, consistent with the Federal income tax due date.)
One might even say that, as thus formulated, the real filing due date is October 15.