The major objective of the study is to investigated the effects of harsh environment and sustained torsion on the structural properties of glass/epoxy composite materials. These effects were studied in terms of degradation in physical and mechanical properties. Samples were loaded at three different twisting angels which includes 20°, 40°, and 60° and immersed in seawater at room temperature (23°C) and 65°C for the duration of 3 months. The results show that seawater absorption increased with immersion time and temperature at 23°C and 65°C. The moisture causes swelling and breakdown of chemical bonds between fibre and matrix at the interface. It is also observed that the crack formation and degradation mechanism accelerated at elevated temperature and large twisting angle in the E-glass epoxy composite but no significant change was observed in modulus of elasticity of the composite.