This design project's purpose is to build a wearable physical monitor that measures and tracks the activity level of submariners. The design consists of several accelerometers being worn at locations across the submariner’s body including the arms, legs, and trunk. The accelerometers along with accompanying electronics and power supply are being placed in protective 3D printed housing. These devices are low-profile and unobtrusive, ensuring they do not interfere with the user’s daily activities, and lightweight, making them unnoticeable during movement. The accelerometers measure the magnitude of acceleration which is used to calculate the submariner’s activity level. This valuable information can be monitored by medical staff to ensure that submariners are maintaining their combat-ready fitness during long deployments in the confined spaces of a submarine.