
© Scubapro, Stephen Frink
Ago Island
Agojima Island in Onagawa, is a beginner-friendly site just 5 minutes by boat from Onagawa Port. With 11–12 m depth, rugged reefs, and narrow waterways, it offers scenic terrain. Year-round residents include pink dungfish, beaked sculpin, and true booyahs, while strong tides bring rich seasonal migratory fish.