R.I. Gen. Laws § 44-11-3 — Filing of returns — Due date

(a) For tax years beginning before January 1, 2016, 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:
(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 as the tax administrator may prescribe, shall be filed with the tax
administrator by the taxpayer taxed as an S corporation and shall be filed on or before
the date a federal tax return is due to be filed, without regard to extension.
(c) 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 taxed as a C corporation and shall be filed on or
before the date a federal return is due to be filed, without regard to extension.
(d) Notwithstanding the provisions of subsections (a) and (c), a C corporation with a
tax year ending June 30 shall, in accordance with federal tax filing requirements,
not change its filing date until mandated by federal law which is currently due to
be effective close of fiscal year ending June 30, 2026.