***ONLY SEAPORT MAC HOLDERS are eligible for award under this solicitation.*** Request for Proposal (RFP) under the Seaport NxG Multiple Award Contract (MAC), number N6133126R3102 for the Unmanned Maritime Systems (UMS). This RFP will also be posted within the Seaport NxG Opportunities Page. This effort has been previously been posted within the Seaport NxG portal under the Opportunities page as the following: Source Sought Notice N61331-25-SN-Q31, dated 6/13/2025 and the follow-up Advance Planning Notice/Pre-Solicitation Notice dated 8/20/2025. Previous references this potential solicitation as number N6133125R3009. *** RESPONSES MUST BE SUBMITTED VIA THE PIEE SOLICITATION MODULE.*** ***UPDATE 12/8 This announcement was posted in the Seaport opportunities page, PLEASE UTILIZE THE DOCUMENTS FOUND WITHIN THE SEAPORT ANNOUCEMENT, Opportunity - Unmanned Maritime Systems RFP N6133126R3102. Opportunity Type: Other.*** UPDATE 12/19 Response time updated to 01/16/2026 4 PM CST ****.Please refer to the Amendment Log found within the Seaport announcement for updates to the RFP.