Best time to dive Yonaguni
Schooling hammerheads are most consistent January–March, within a season that runs roughly November to May. The winter northeast monsoon cancels many days; avoid July–September typhoons.
Peak season: December–March
Overall diving, month by month
Balanced scoring · forecasts include the 2026/27 El Niño outlook
Confidence: Nov high · Dec high · Jan medium · Feb medium · Mar medium · Apr medium · May medium · Jun medium · Jul medium · Aug medium · Sep medium · Oct low · Nov medium · Dec medium
What's good when
Each attribute scored 0–10 for every month
| Nov2026 | Dec | Jan2027 | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pelagic & big animals | 7 | 8 | 9 | 9 | 9 | 7 | 5 | 5 | 5 | 5 | 5 | 5 | 7 | 8 |
| Macro life | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
| Coral & reef health | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 3 | 3 | 3 | 3 | 4 | 4 |
| Visibility | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 |
| Water temperature | 8 | 6 | 5 | 5 | 5 | 6 | 8 | 9 | 10 | 10 | 10 | 9 | 8 | 6 |
| Weather & sea state | 6 | 5 | 5 | 5 | 5 | 7 | 7 | 7 | 6 | 5 | 6 | 7 | 6 | 5 |
| Operations & access | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 |
Climate outlook
How this year's forecast differs from a typical year
- Coral & reef health -1.3 · Summer bleaching risk in the year after a strong El Niño (Jul 2027 – October 2027)
Water temperature & visibility
| Month | Water | Visibility |
|---|---|---|
| November 2026 | 25.5 °C (78 °F) | 30–40 m |
| December 2026 | 24.0 °C (75 °F) | 30–40 m |
| January 2027 | 22.5 °C (73 °F) | 30–40 m |
| February 2027 | 22.0 °C (72 °F) | 30–40 m |
| March 2027 | 22.5 °C (73 °F) | 30–40 m |
| April 2027 | 24.0 °C (75 °F) | 30–40 m |
| May 2027 | 26.0 °C (79 °F) | 25–35 m |
| June 2027 | 27.5 °C (82 °F) | 25–35 m |
| July 2027 | 29.0 °C (84 °F) | 25–35 m |
| August 2027 | 29.0 °C (84 °F) | 25–35 m |
| September 2027 | 28.5 °C (83 °F) | 25–35 m |
| October 2027 | 27.0 °C (81 °F) | 25–35 m |
| November 2027 | 25.5 °C (78 °F) | 30–40 m |
| December 2027 | 24.0 °C (75 °F) | 30–40 m |
Marine life calendar
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| scalloped hammerhead | Peak | Peak | Peak | ● | ● |
Peak = best odds · ● = regularly seen · blank = unlikely. Calendar months, every year.
About the diving
- Difficulty
- Advanced
- Current strength
- 5 / 5
- Luxury level
- 1 / 5
- Typical depth
- 10–35 m
- Max depth of interest
- 40 m
- Dive styles
- Day boat
- Suggested certification
- Advanced Open Water + strong-current experience
- Nearest airport
- OGN
- Snorkelling
- Limited
- Known for
- scalloped hammerhead, Yonaguni Monument
Famous sites: Iseki Point (Monument) · Hammerhead Point · Irizaki · Tachigami Rock
Season notes & sources
- Schooling hammerheads are most consistent January–March, within a season that runs roughly November to May. The winter northeast monsoon cancels many days; avoid July–September typhoons.