The underwater environment is challenging due to the available three-dimensional space and the risk of water damaging electronic and mechanical parts. Using 3D printing technology, a housing as well as the functional parts for an underwater robotics kit can be produced low-priced at home or in schools and other facilities. Other mechanical parts used in the design are standardized and available in common home improvement stores. Conveniently the robot is designed modular, facilitating easy assembly and the possibility to test the functionalities of each module outside the housing. The used Hedgehog robotics controller is focusing on low costs in the hardware, and is extended by high usability in the software for this underwater robotics kit.