The behavior of a woven E-glass–Vinylester composite in dry and seawater-saturated conditions was investigated for strain rates in the range of 0.001–100 s ^{– 1}. Reliable data were obtained by conducting servo-hydraulic tests at high speed with DIC strain measurement. Issues related to inertial effects of the test system and controlling vibrational stress waves were resolved through a unique experimental setup and special attention to specimen geometry and fixturing. In addition, a rate-dependent constitutive model was adapted to characterize the elastic–viscoplastic response at various strain rates and validated by comparison to test data. The subject investigation demonstrates a viable methodology to identify strain rate sensitivities in high speed experiments and develop a representative material model for analysis of high rate phenomena.