Ukon Denchi
Dive site · Japan
Advanced divers and up
Is it worth the trip?
73Good out of 100 for your dates
Best on Thu 5: Sea 0.6 m, Visibility about 15 m, Water 27 °C
Tue 3 · 73 out of 100
- Sea
- 0.8 m
- Wind
- 13 kn
- Gusts
- 17kn
- Air
- 27°C
Wed 4 · 76 out of 100
- Sea
- 0.7 m
- Wind
- 8 kn
- Gusts
- 12kn
- Air
- 27°C
Thu 5 · 77 out of 100
- Sea
- 0.6 m
- Wind
- 2 kn
- Gusts
- 7kn
- Air
- 27°C
Fri 6 · 71 out of 100
- Sea
- 0.8 m
- Wind
- 14 kn
- Gusts
- 20kn
- Air
- 26°C
Sat 7 · 63 out of 100
- Sea
- 1.0 m
- Wind
- 19 kn
- Gusts
- 25kn
- Air
- 26°C
Sun 8 · 70 out of 100
- Sea
- 0.9 m
- Wind
- 15 kn
- Gusts
- 23kn
- Air
- 26°C
Mon 9 · 69 out of 100
- Sea
- 0.9 m
- Wind
- 16 kn
- Gusts
- 23kn
- Air
- 26°C
Tap a day for sea, wind and water. Full forecast
Forecast: next 10 days
Full forecast- Mon 277, good
- Tue 373, good
- Wed 476, good
- Thu 577, good
- Fri 671, good
- Sat 763, good
- Sun 870, good
- Mon 969, good
- Tue 1073, good
- Wed 1173, good
The site in five facts
- Down to 20 mits deepest
- From a boathow you get in
- Advancedand up
- Water 27 °C3 mm wetsuit
- Faces SEswell from there reaches it
Full forecast
every day, every number
The score doesn't know currents, the visibility on the day or your certification.
Suits Advanced divers and up, as a dive guide states it. Scored for Advanced divers.
| Day | Score | Sea | Wind | Gusts | Air |
|---|---|---|---|---|---|
| Mon 2Nov | 77, good | 0.7 m | 4 kn | 7kn | 27°C |
| Tue 3Nov | 73, good | 0.8 m | 13 kn | 17kn | 27°C |
| Wed 4Nov | 76, good | 0.7 m | 8 kn | 12kn | 27°C |
| Thu 5Nov | 77, good | 0.6 m | 2 kn | 7kn | 27°C |
| Fri 6Nov | 71, good | 0.8 m | 14 kn | 20kn | 26°C |
| Sat 7Nov | 63, good | 1.0 m | 19 kn | 25kn | 26°C |
| Sun 8Nov | 70, good | 0.9 m | 15 kn | 23kn | 26°C |
| Mon 9Nov | 69, good | 0.9 m | 16 kn | 23kn | 26°C |
| Tue 10Nov | 73, good | 0.9 m | 13 kn | 20kn | 25°C |
| Wed 11Nov | 73, good | – | 16 kn | 23kn | 23°C |
Sea is the waves near the site, in metres; wind and gusts in knots. "Boats in": gusts that keep dive boats in. More
Tide
- Mon 2 NovLow 05:36 −0.7 mHigh 12:40 +0.3 mLow 17:52 −0.0 mHigh 23:45 +0.5 m
- Tue 3 NovLow 06:58 −0.6 mHigh 13:51 +0.4 mLow 19:33 −0.2 m
- Wed 4 NovHigh 01:27 +0.5 mLow 08:10 −0.5 mHigh 14:44 +0.5 mLow 20:45 −0.3 m
Local clock times; heights about mean sea level. On open coasts the times are usually within a quarter of an hour; in bays, estuaries and on the Gulf of Mexico they can be an hour or more out. Slack water, the safest time to dive where there is current, is about half an hour either side of each high and low. Tide: EOT20 global ocean tide model, Hart-Davis et al. 2021, DGFI-TUM (doi:10.17882/79489), CC BY 4.0. Times and heights computed by us. A model, not a tide table: check a local table before you go.
Forecast updated . It refreshes every three hours. Forecast data: ECMWF, DWD, Météo-France and NOAA, served by Open-Meteo.com (CC BY 4.0). Changed by us. Generated using E.U. Copernicus Marine Service Information.
Best time to go
No month stands out
Good diving days in a typical week, each month, for Advanced divers, from 2016 on (ERA5 history scored the same way).
- Jan6of 7: a trip from Sat 2 Jan
- Feb6of 7: a trip from Sat 6 Feb
- Mar7of 7: a trip from Sat 6 Mar
- Apr7of 7: a trip from Sat 3 Apr
- May7of 7: a trip from Sat 1 May
- Jun7of 7: a trip from Sat 5 Jun
- Jul7of 7: a trip from Sat 3 Jul
- Aug7of 7: a trip from Sat 7 Aug
- Sep6of 7: a trip from Sat 4 Sept
- Oct6of 7: a trip from Sat 2 Oct
- Nov6of 7: a trip from Tue 3 Nov
- Dec5of 7: a trip from Sat 5 Dec
Tap a month to see this spot for a trip then.
Typical, not a forecast: the sea and the mean wind of each day, with no gusts or rain in the history.
Map
the site and its town
Ukon Denchi on Google Maps · Directions
Each place wears its best day on these dates: green good, amber fair, pale red poor, as the key says.
The map needs JavaScript. Every place on it is listed on this page, and each place's page links to Google Maps.
One finger scrolls the page; two fingers move the map. Pins are our own positions. Map OpenFreeMap, © OpenMapTiles, data © OpenStreetMap contributors.
More diving near here
1 place
- Middle Book 2.7 km away
About
the place in full, sources, credits
About Ukon Denchi
A reef dive. It goes down to 20 m. You get in from a boat. It suits Advanced divers and up, as a dive guide states it. The coast faces SE: swell from the SE reaches it, and wind from the NW blows out to sea. No dive centre within 10 km, the nearest 10 km away. The sea is about 23°C in February, its coldest month (5 mm wetsuit), and 30°C in August, its warmest (rash vest or 1 to 2 mm). The town to stay in is Ishigaki. Within 5 km we also list 1 dive site.
- What it is Reef.
- How deep Down to 20 m.
- Getting in From a boat.
- Who it suits Suits Advanced divers and up, as a dive guide states it.
- Dive centres No dive centre within 10 km, the nearest 10 km away.
Water about 27°C: 3 mm wetsuit. Typical sea temperature for the time of year, not a forecast.
Visibility about 15 m. Typical for the time of year, estimated from ten years of NASA satellite water clarity, not a forecast. Clearest in Jan, Nov and Dec (about 15 m).
The score is the conditions only: the journey, the price and the partners never change it (how we score, how we earn).
Rough cost (estimate): about US$1,250–US$2,450 each
about US$1,250–US$2,450 each · 6 nights, 2 sharing: flights, taxi, stay, food.
Our estimate from typical public prices, not a quote: check the real prices before you book (where they come from). Prices are about, in US Dollar (USD): our pound figures at the European Central Bank's rate of 30 October 2026.
How we worked it out
| What | How we worked it out | Each |
|---|---|---|
| Flights | return ORD to ISG, estimated from distance and season, changing at HKG, full-service airlines, with a hold bag | about US$757–US$1,570 |
| Taxi | airport and back, shared | about US$47–US$80 |
| Stay | 6 nights, a mid-range double, shared | about US$208–US$348 |
| Food | 7 days eating out | about US$234–US$442 |
| Total | about US$1,250–US$2,450 |
Guided dives are not priced yet: we have no sourced price, so it is not in it. Prices from public sources, checked in 2026.
Where to stay: Ishigaki
about 20 min by car · 116 places to stay
about US$80/nightcountry average
About Ishigaki its beds, food and every spot near it
About US$80 a night is our estimate of the country's average 2-star double room that month: not each town's price, and not a quote. Drives are estimates. Prices are about, in US Dollar (USD): our pound figures at the European Central Bank's rate of 30 October 2026.
Getting there: about 25h 50m
About 25h 50m door to door from Chicago
Fly ORD → ISG, changing at Hong Kong International Airport (HKG), then 40 min by road
Flights ORD → ISG on your dates · Skyscanner
An estimate, one way; the journey never changes the score.
In the water
Dives and courses in Ishigaki · GetYourGuideDive gear hire in Ishigaki · GetYourGuide
Dive centres nearby
HAMAマリンサービス 10 km
石垣島トータルマリン 10 km
Prime Scuba Ishigaki 12 km
海講座 20 km
ファンシー 22 km
The nearest named dive centres and shops within 25 km, in a straight line; training agencies where the map states them. Listings, not a recommendation. Dive centres: © OpenStreetMap contributors (ODbL). Credits
What you might see
Too few open records near this site to list its animals. Ask a dive centre what you are likely to see.
This week's visibility, the current and the life no free forecast gives. Ask a dive centre before you book.
Saved: this link opens the same trip
The link holds the trip itself: nothing about you is kept. Check the forecast again before you book.