<p><i>Istigobius campbelli </i>is a sand-dwelling goby commonly found in coastal waters of the western Pacific and has yet to have its species-specific behaviors documented in peer-reviewed literature. Recently, it has been increasing in numbers along the northern part of its historical range while, at the same time, longer-established species of sand-dwelling gobies, such as <i>Acentrogobius virgatulus</i>, have seen numbers decline in recent years. Here, observational behavior recordings were performed, in situ, during the breeding season (May to August) using handheld and remote underwater video cameras to describe its interactions with other species and between conspecifics. Artificial reefs were later installed to provide nesting habitat and facilitate behavioral recordings. Reproductive, agonistic, and interspecific behaviors were documented, then organized into an ethogram and categorized by context and characteristics. These behaviors included nest maintenance, courtship, agonism, and other ambiguous behaviors. Many behaviors seen here have been reported in other species of Gobiidae, but often in distinctive combinations, particularly in the case of agonistic bouts and courtship. It is possible that these behaviors are influenced by their preferred habitat and physiology. Future studies can utilize the observations made here to extrapolate greater trends in goby behavior and interspecific interactions as ocean warming continues to mix communities.</p>