In 2007, the project titled, “A day in the life of spinner dolphins,” aimed to propose a research plan to achieve a preliminary understanding of the distribution and behavioral ecology of spinner dolphins (Stenella longirostris (Gray, 1828)) inshore of Hualien, eastern Taiwan. This was achieved by conducting systematic observations and behavioral recordings, by studying the dolphins throughout day without causing any disturbance to them. The acquired dataset includes all the cetacean sighting records of this study.