Heinaicho is a shallow shore-entry reef site located in the Sea of Japan. The site reaches a maximum depth of 5 metres, making it accessible for beginners and snorkellers. Conditions are generally manageable due to a mild current, though visibility is variable and can change significantly between visits. As there are no confirmed facilities at this location, visitors should arrive prepared with all necessary equipment, drinking water, and a change of clothes. The site is accessible year-round, with water temperatures fluctuating between 9 and 24 degrees Celsius depending on the month. Always check local conditions and visibility before entering the water.