The construction industry is increasingly seeking sustainable alternatives to natural sand due to its rapid depletion and environmental impact. Marine dredged sediments have emerged as a promising solution, offering both ecological and economic benefits. This study investigates the potential of dredged sediments from Jebha Port, northern Morocco, as a partial replacement for dune sand in concrete. Twelve sediment samples, collected from various locations within the port, were thoroughly analyzed to determine their physical, chemical, and mineralogical properties. These sediments, primarily composed of fine sands, were incorporated into concrete equivalent mortars (MBE) at substitution rates of 10%, 25%, 50%, and 100%. To optimize workability and mechanical performance, two advanced superplasticizers—Sika ViscoCrete-25 M Tempo and Sika ViscoCrete-1700 Tempo M—were tested. The findings reveal that replacing sand with dredged sediments influences the rheological and mechanical behavior of the mortar, with higher substitution levels presenting both challenges and opportunities. This research highlights a sustainable approach to reusing marine dredged sediments in the construction industry while ensuring material performance. The results confirm that at optimal substitution levels, these sediments can enhance the sustainability of construction materials without significantly compromising their mechanical properties.