Isonoura 20.8
#5628 of 5756 surf spots in the world · 🇯🇵 Japan · Wakayama · near Wakayama
Needs the right swell, wind is the enemy here, peaks in September.
Best time to surf Isonoura
The best time to surf Isonoura is September. It rarely works. In September the water sits around 27°C, so pack boardshorts, and the typical wave is 0.3 m. The nearest airport is KIX (24 km) and the nearest town is Wakayama (8 km).
| Month | Surfable | Clean | Size | Water | Suit |
|---|---|---|---|---|---|
| Jan | 36% | 0% | 0.5 m | 13°C | 5/4 |
| Feb | 28% | 0% | 0.4 m | 11°C | 5/4 |
| Mar | 23% | 0% | 0.3 m | 12°C | 5/4 |
| Apr | 21% | 0% | 0.3 m | 16°C | 3/2 |
| May | 14% | 0% | 0.3 m | 18°C | 3/2 |
| Jun | 14% | 0% | 0.3 m | 22°C | 2mm |
| Jul | 17% | 0% | 0.3 m | 26°C | boardies |
| Aug | 16% | 0% | 0.3 m | 28°C | boardies |
| Sep | 15% | 2% | 0.3 m | 27°C | boardies |
| Oct | 13% | 0% | 0.3 m | 24°C | vest |
| Nov | 18% | 0% | 0.2 m | 21°C | 2mm |
| Dec | 34% | 0% | 0.5 m | 17°C | 3/2 |
What is under Isonoura
Eight kilometres out along its swell window the sea floor falls away into open ocean, 1,233 m, deep right up to the door, so swell arrives with its energy intact. Alongside the bank the survey finds a channel, 1684 m against 1233 m, deep enough to bend swell onto one peak instead of spreading it along the beach.
Measured, not estimated: NOAA ETOPO 2022 global relief at 15 arc-seconds, about 460 m per cell, sampled along this spot’s own swell window. At that scale the survey sees passes and channels; it cannot see a reef ledge, so nothing here is said about how the wave breaks.
Why 20.8
Seven parts, each normalised 0 to 1 and multiplied by its weight; the sum is scaled so the best spot in the world scores 100. Wave quality and what the spot does on its best days carry more than half of it, which is what separates this from a ranking of where the water is warm.
The detail
Faces 230° with 28% open water around it. Friendly morning wind 60% of days. Mean peak period 4.5 s. Days over 3 m: 0%. On its best tenth of days it reaches 0.8 m, with a peak period of 6 s. Mellow days (0.4 to 1.2 m): 36%. Months that work: 0 of 12. Coordinates 34.259, 135.095 (OpenStreetMap).
What it costs to be here
Airport and town on the doorstep, so the local estimate is 23% above the country average. Estimate: World Bank PPP price level for Japan (2025, United States = 1.00) applied to a fixed surfer basket, then adjusted for how remote the spot is. Your own number moves with the season and how you live.
Sumba has eight spots in this ranking, the best of them inside the world top 50. A cabin is €11,500. The land it sits on is separate, from €6,500 (€9,950 oceanfront), on an 80-year lease that extends at the end. Water, septic and electricity are another €6,500, and furniture is on top, so a finished cabin lands around €28,000 plus the land, payable in instalments.
Eco Beach City is run by the same people as SurfRanking, so treat this as our own advert, not a recommendation. It is an off-plan property in Indonesia: take your own legal and financial advice before paying anything.
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