Miura and Jogashima lie on Sagami Bay, south of Tokyo, making them among the most accessible ocean dive areas from the capital. The nine sites in our database cover a wide range of formats, from shallow shore entries suited to beginners through to boat-access drift dives and deeper walls for advanced divers. The area rewards patient macro hunters: nudibranchs, seahorses, frogfish, and cuttlefish are all recorded here, and visibility improves noticeably in winter when plankton levels drop. Water temperatures follow a clear seasonal swing, sitting in the mid-to-upper teens through winter and rising to the mid-twenties in late summer.
Monthly water temperature across Miura & Jogashima's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Visibility is often limited in summer due to plankton but sharpens considerably in winter, making the cooler months the preferred season for photography and macro work. Water temperatures drop into the mid-to-upper teens from winter through early spring, so a drysuit or thick wetsuit is advisable for extended dives during that period.
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Water temperature around Miura & Jogashima ranges from about 17°C in January to 26°C in September, based on satellite sea-temperature data for its dive sites.
In the warm season (about 26°C) a 3mm full suit is comfortable in Miura & Jogashima; in the coldest months (about 17°C) step up to a 7mm or semi-dry suit.
Fin maps 9 sites in Miura & Jogashima (8 scuba diving sites).
Across Miura & Jogashima's dive sites, May, September and November are most often reported as the best months to visit.
2 more sites to explore
