Nipponopelta is the first ankylosaur discovered in Japan. It was a medium-sized nodosaur, at approximately 5 m in length. Typical of ankylosaurs, Nipponopelta was a quadrupedal herbivore covered in spikes and osteoderms down its back and tail. Interestingly, Nipponopelta is more closely related to North American nodosaurids than to its Asian contemporaries.