down to 10 m
Hidden gem
Susami Underwater Postbox
A working postbox 10 m down in Susami Bay, officially part of the Susami post office; divers post special waterproof plastic postcards.
- Open Water
Susami Bay
Diving in Japan
A dive in Japan that is worth the trip on its own. Diveable all year.
- Good months
- All year
- Levels
- Open Water
When to go
Pick a month: the diving season, from published sources, and the typical weather.
Pick a month
- Best
- Good
- Possible
- Closed
- Not documented yet
Susami Bay in October
Good season- Sea
- 26 °C
- at the surface
- Air
- 24 °C
- 18 °C at night
- Rain
- 190 mm
- average for the year
- Wind
- 13 km/h
- on average
Typical weather, not a forecast: averages for 2021–2025 (air, rain, wind) and 2023–2025 (sea), data from Open-Meteo (ERA5 / Copernicus, Météo-France). Covers an area of roughly 10 to 25 km around the destination.
Local operator Club Noah Susami lists try-dive (with postcard posting) session times for both June–October and November–May, i.e. dives are offered year-round. No best months stated. A Club Noah fun-dive plan requires dry suit experience, suggesting cold-water gear in the cool season.
The dive
Open Water friendly
usual dive down to 18 m1 siteWhere is Susami Bay?
Susami Bay: frequently asked questions
- When is the best time to dive Susami Bay?
- Susami Bay can be dived all year round. Local operator Club Noah Susami lists try-dive (with postcard posting) session times for both June–October and November–May, i.e. dives are offered year-round. No best months stated. A Club Noah fun-dive plan requires dry suit experience, suggesting cold-water gear in the cool season.
- Is Susami Bay good for beginner divers?
- Yes, partly: 1 of the 1 dive sites we document are suited to Open Water divers, including Susami Underwater Postbox. The others need more experience or a higher certification.
About this page
Seasons and marine life come from the sources below. Site levels and depths marked as estimated come from our original catalogue and are being checked one by one. Conditions change: always confirm with a local dive centre.
Your next dive is somewhere out there.
Find my next dive tripPhoto credits
- Sunlight and bubbles in deep blue water, Sarah Lee, Unsplash License, on Unsplash