This report describes the full-scale evaluation of prototype submersible matting systems (SUBMAT) at a test site at the US Army Engineer Research and Development Center’s Vicksburg, Mississippi, site. The SUBMAT prototypes were designed to bridge the gap between high and low tide at a beach interface to enable 24-hour operation at an expeditionary watercraft landing site. This phase of the SUBMAT prototype development was intended to determine prototype system durability by applying military vehicle loads representing a combat brigade insertion across a littoral zone. The two mat systems evaluated in this study were the PYRACELL Road Building System (PRBS) and a basaltic rebar mat system. The results of the study showed that the PRBS system was able to sustain 1,000 Medium Tactical Vehicle Replacement, 350 Heavy Expanded Mobility Tactical Truck, and over 150 M1A1 main battle tank passes without significant damage. The basaltic rebar mat failed early in the test and was removed from further consideration for the SUBMAT application. Observations and lessons learned from this phase of the prototype PRBS development will be used to improve the PRBS design and modify its installation procedures for improved efficiency.