The CastAway-CTD was designed specifically for coastal profiling and it incorporates a 6-electrode conductivity cell, coupled with a fast response thermistor to provide highly accurate, high resolution CTD measurements to depths of 100m. The system incorporates modern technical features which allow it to achieve a 5 Hz response time, fine spatial resolution, and high accuracy. It is an easy to deploy instrument that does not require a pump and is hydrodynamically designed to free fall at a rate of 1 m/s. There is an integrated real-time data display screen, internal GPS sensor, and automated wireless data transfer that are unique features to simplify data collection.