R.I. Gen. Laws § 44-14-6 — Filing of annual return

(a) Every taxpayer shall file a return with the tax administrator:
(1) In case the taxable year of the taxpayer is the calendar year, on or before March
15 in the year following the close of the taxable year; and
(2) In case the taxable year of the taxpayer is a fiscal year, on or before the fifteenth
(15th) day of the third (3rd) month following the close of the fiscal year.
(b) For tax years beginning after December 31, 2015, a return, in the form and containing
the information that the tax administrator may prescribe, shall be filed with the
tax administrator by the taxpayer on or before the date a federal return is due to
be filed, without regard to extension.