This study investigates the response of flexible piezoelectric materials exposed to blast wave pressure impulses from inair and underwater explosions. A shock tube was used to produce reproducible shock waves from explosions with average peak pressures in excess of 1,000 kPa for underwater experiments and 100 kPa for in-air experiments. Flexible piezoelectric polyvinylidene fluoride (PVDF) and lead zirconate titanate Pb(Zr,Ti)O3 (PZT) materials were tested for sensing the pressure impulse generated from an explosion. The rise time, peak amplitude, and duration of the blast wave pressure impulse were measured for each piezoelectric material and compared to an OEM blast wave sensor. This study uniquely identifies flexible piezoelectric materials that can accurately measure the blast wave pressure impulse from both in-air and underwater explosions. The accurate response and flexibility of the selected piezoelectric materials demonstrate the potential to be integrated into several forms of sensors, including wearable. Military and industrial applications can potentially benefit from a wearable blast wave sensor to improve medical diagnosis and treatment of blast exposure.