November: The Best Diving Month Most Divers Miss

Many divers think the diving season ends with summer. However, our data tells a different story: November is the sweet spot where water temperature and visibility are both favorable. Water temperatures remain above 21°C -- perfectly comfortable in a wetsuit -- while summer plankton blooms subside and visibility begins its climb toward the winter peak.

November Data for Key Sites

Why November Is the Sweet Spot

1. Water Is Still Warm

November water temperatures remain above 21°C at all sites: 21.1°C in the Izu area, 22.7°C at Kashiwajima, and 22.9°C at Kushimoto. A 5mm wetsuit is perfectly comfortable at these temperatures -- no drysuit needed yet. Kerama is a balmy 25.8°C, comfortable even in a thin wetsuit.

2. Visibility Is on the Rise

As plankton activity gradually declines from summer through autumn, visibility clearly begins improving in November. IOP at 14.7m and Ito at 15.0m represent a 2m+ improvement over summer levels of 12-13m, on an upward trajectory toward the winter peak of 17-18m.

3. Fewer Crowds

Compared to the summer high season, November sees significantly fewer divers. Popular sites have shorter waits, and dive shops are more likely to offer small-group guiding. Booking is easier, and the overall experience is more relaxed.

Regional November Highlights

Izu Area (IOP 14.7m / 21.1°C)

Izu sees a notable visibility improvement starting in November. At 21.1°C, a 5mm wetsuit is perfectly adequate. It is an excellent time for observing soft coral colonies and nudibranchs. While visibility continues to improve into winter, water temperature drops rapidly, making November the month with the best balance of both factors.

Shikoku & Kii Peninsula (Kashiwajima 14.2m/22.7°C, Kushimoto 12.9m/22.9°C)

Kashiwajima and Kushimoto maintain water temperatures above 22°C in November, with visibility on an improving trend. Kashiwajima is one of Japan's premier macro diving destinations, and autumn to winter is when gobies and nudibranchs are at their most abundant.

Okinawa (Kerama 19.2m / 25.8°C)

Kerama remains warm at 25.8°C with excellent 19.2m visibility. Typhoon season is over and weather becomes stable, making this a hidden gem season for Okinawa diving.

Preparing for November Diving

• Gear: Izu and Chiba need a 5mm wetsuit + hooded vest. Shikoku and Wakayama are fine with 5mm. Okinawa needs just 3mm
• Transport: Autumn foliage season means traffic congestion on weekends heading toward Izu
• Early sunset: Sunset is around 16:30 in November. Plan afternoon dives earlier than in summer

Summary

• All sites maintain water temperatures above 21°C in November (wetsuit-comfortable)
• Visibility improves 2m+ from summer, trending toward winter peak
• Kerama at 19.2m/25.8°C offers the best November balance
• Izu area at 14.7m/21.1°C is also excellent
• An uncrowded off-peak season with comfortable conditions