The use of underwater robots and vehicles in order to observe marine environments, work undersea, and develop seabed resources has increased in recent years. One such robot is a fishlike robot that swims by wriggling its body and fins instead of being propelled by rotating thrusters. Fish have various swimming styles, and there are advantages and disadvantages to each. It is known that the carangiform and subcarangiform swimming motions offer superior acceleration and advance, so in this study, we developed and assessed a fishlike robot that imitates these motions.