Udone-shima
Island Volcanic island in Tokyo's island chain
Udone-shima is a small volcanic islet in the Izu archipelago administered by Tokyo Metropolis. It is uninhabited and much smaller than the better-known Izu Islands.
Sheer coastal cliffs and rocky shorelines dominate the islet; it is visited mainly by naturalists and experienced boaters rather than general tourists. The islet offers seabird habitat and coastal marine scenery but has no visitor facilities.
Formed by volcanic processes related to the Izu-Bonin arc, the islet is one of many minor volcanic outcrops in this part of the northwest Pacific. It has no significant modern settlement or development.
Udone-shima lies in the Philippine Sea within Tokyo Prefecture’s island district, part of the wider Izu island chain. The islet is offshore from the Izu main islands and reachable only by private sea craft.
- Access: There are no regular public transport services to the islet; visit requires private boat arrangements and permission where applicable.
How to Get to Udone-shima #
Udone-shima is reached by local ferries or charter boats from ports on Honshu (for example, Tokyo-area marinas), depending on seasonal services; check regional ferry schedules and weather conditions before travel.
Tips for Visiting Udone-shima #
- If visiting from Tokyo, check boat schedules and weather reports - seas around the Izu islands can be rough.
- Bring waterproof clothing and sturdy footwear; landing stages are minimal on small volcanic islets.
- Respect restricted zones - some islands are protected for wildlife or have private ownership and limited access.
Best Time to Visit Udone-shima #
Summer and the shoulder seasons offer the most convenient sea conditions for island trips from Tokyo; always check ferry timetables and weather.
Weather & Climate near Udone-shima #
Temperate climate with hot summers (peaking in August) and cold winters (coldest in February). Temperatures range from 7°C to 28°C. Heavy rainfall (2377 mm/year), wettest in June.
January
January is cool with highs of 13°C and lows of 8°C. Significant rainfall (113 mm) and partly cloudy skies.
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February
February is the coolest month with highs of 13°C and lows of 7°C. Significant rainfall (129 mm) and partly cloudy skies.
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March
March is cool with highs of 14°C and lows of 8°C. Significant rainfall (196 mm) and partly cloudy skies.
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April
April is cool with highs of 18°C and lows of 12°C. Heavy rain (203 mm) and partly cloudy skies.
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May
May is mild with highs of 21°C and lows of 15°C. Heavy rain (216 mm) and mostly overcast skies.
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June
June is mild with highs of 23°C and lows of 19°C. The wettest month with heavy rain (291 mm) and mostly overcast skies.
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July
July is warm with muggy conditions (dew point 23°C). Significant rainfall (196 mm) and mostly overcast skies.
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August
August is the warmest month with stifling humidity (dew point 24°C). Heavy rain (216 mm) and partly cloudy skies.
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September
September is mild with highs of 26°C and lows of 21°C. Heavy rain (269 mm) and partly cloudy skies.
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October
October is mild with highs of 22°C and lows of 17°C. Heavy rain (257 mm) and partly cloudy skies.
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November
November is cool with highs of 19°C and lows of 14°C. Significant rainfall (181 mm) and partly cloudy skies.
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December
December is cool with highs of 16°C and lows of 10°C. Significant rainfall (110 mm) and partly cloudy skies.
