<p>Marine clays often exhibit low strength and poor dynamic resistance, posing challenges for infrastructure development in coastal regions. While cement-treated clays’ static and dynamic behavior has been widely investigated, limited research exists on marine clays’ cement-fly ash stabilization, particularly under cyclic loading. This study examines the static and dynamic responses of Indian marine clay treated with varying proportions of cement-fly ash blends, emphasizing strain–dependent behavior through cyclic triaxial testing. A comprehensive experimental program was undertaken to evaluate unconfined compressive strength (qu), shear wave velocity (V_s), maximum shear modulus (G_max), shear modulus (G), damping ratio (D), and strain-dependent properties as functions of curing period and binder dosage. The results demonstrate substantial improvements in the stabilized clay’s strength and dynamic performance, primarily due to the formation of cementitious compounds such as calcium silicate hydrate (C-S-H) and ettringite, as confirmed by X-ray diffraction analysis. The development of these compounds reduced void ratios and created a denser soil matrix, thereby enhancing stiffness, strength, and energy dissipation capacity over time. These findings provide new insights into using cement-fly ash blends to improve the seismic resilience of marine clay deposits in coastal and offshore geotechnical applications.</p>