The paper describes the main features and initial underwater field-testing results of a remotely operated submersible drill rig designed to obtain continuous cores of soil and/or rock up to 6m long in water depths of 200m. The rig mast angle is hydraulically actuated covering 90° of altitude. This enables both a fully horizontal position used for deployment onto, and recovery of the rig from, the seabed, as well as a fully vertical position during coring. The frame is equipped with positioning and inclination sensors for accurate register of core orientation. Coring equipment with diameter of up to 133mm can be mounted in the rig, thus enabling the recovery of relatively large-diameter cores. The coring operation is fully instrumented and all the drill operation parameters such as torque, thrust, advance, injection rate and pressure are recorded. The equipment is deployable from a variety of platforms.