A water-activated bobber release device is used to retrieve a submerged item to which it is attached. The device has a housing, a spring, a bobber assembly having a bobber, a spool and a central hole, a bobbin assembly having a framework surrounding a center hole and a dissolvable tablet within the framework, a screw having a flared head engaging the framework and an elongated threaded section extending through the central hole and the center hole, and a fastener connected to the screw holding the spring in compression when the tablet is solidified. The device also has a line wrapped around the spool connecting the bobber assembly to the housing or the item. When submerged in water, the tablet dissolves, and the spring forces the screw's head through the bobbin assembly, thereby jettisoning the bobber assembly from the housing where it is free to float to the surface for retrieval.