R.I. Gen. Laws § 44-11.1-3 — Filing of tax returns — Due date

A tax return in the form and containing the information that the tax administrator
may prescribe shall be filed with the tax administrator by the political organization:
(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.