Houston Mechatronics Inc. (HMI) is developing a subsea robot named Aquanaut featuring multi-jointed robotic arms designed to interact with subsea equipment. There is a need for joint-level torque sensing to enable advanced control schemes for Aquanaut’s manipulator arms. Using strain gauges placed on a harmonic drive, we proposed an accurate torque measurement model for HMI’s subsea actuators. Four half-bridge strain gauges are placed around the flexspline to negate strain changes from harmonic drive operation. A symmetric full bridge configuration allows for the cancellation of uniform temperature and pressure changes by taking the relative difference in the strains. We also incorporate the actuator output position in our torque measurement model to account for errors due to actuator assembly pre-loading. The results were incorporated into HMI’s company workflow for integration with Aquanaut’s manipulator arms.