Amendment 0003: Amendment 0003 attaches Solicitation DD Form 254. Amendment 0002: Amendment 0002 deletes H-209-PAC005 text. Amendment 0001: Amendment 0001 attached a Question and Answer. The RFP response date is extended until 11 December 2025 at 15:00 Pacific. The Naval Information Warfare Center (NIWC) Pacific is issuing Request for Proposal (RFP) No. N6600126R0018 for Unmanned Maritime Systems Support (UMSS). The services contemplated under this effort will provide the Navy with specification and design, fabrication, development, integration, assembly, installation, test, evaluation, demonstration, fielding, operations, maintenance, training, logistics, documentation, administration, configuration management (CM), and program management (PM) of both hardware and software in support of unmanned maritime systems engaged in supporting U.S. Navy missions under contract with Naval Warfare Information Center (NIWC) Pacific. The scope of this contract is intended to cover current systems being supported, as well as any future waterborne and underwater systems and technologies in the following maritime system mission areas: explosive ordnance disposal (EOD); mine countermeasures (MCM); force protection (FP); intelligence, surveillance, and reconnaissance (ISR); mine warfare (MIW); anti-submarine warfare (ASW); and other specialized undersea and surface unmanned systems applications.It is anticipated that the procurement will result in the award of multiple indefinite-delivery, indefinite quantity (IDIQ) contracts with cost-plus-fixed-fee (CPFF) and cost (no fee) pricing arrangements. The period of performance will include an eight-year ordering period. Orders will be placed pursuant to the ordering processes of FAR 16.505(a). The North American Industry Classification System (NAICS) Code is 541330 Engineering Services (Except (a), Military and Aerospace Equipment and Military Weapons) and the Small Business Size Standard is $47 M. Security classification will vary from Unclassified to Top Secret/Incidental Sensitive Compartmented Information (TS/SCI) classification. This requirement will be competed on a full-and-open basis. This is a follow-on requirement covered by contracts N6600121D0132 through 0140. The solicitation will be availability electronically via the PIEE solicitation module. Hard copy versions of the RFP and any subsequent amendment(s) will not be available.Firms are encouraged to review the website regularly for important solicitation information.For questions concerning this action, contact Paige Miller, Contract Specialist, at paige.r.miller5.civ@us.navy.mil.Note: A Pre-Solicitation notice was posted for this procurement on 30 September 2025 under Procurement Integrated Enterprise Environment (PIEE) solicitation module notice ID N66001_25_R_0024. The solicitation number for this procurement is now N6600126R0018.