R.I. Gen. Laws § 36-10.3-7: Vesting of contributions.

(1) The total amount contributed by the member, including associated investment gains and losses, shall immediately vest in the member and is non-forfeitable.

(2) The total amount contributed by the employer, including associated investment gains and losses, vests with the member and is nonforfeitable upon completion of three (3) years of contributory service. Service credited under ERS or MERS prior to the effective date of this plan shall be credited to members for vesting purposes.