This route runs from Shimanto City in Kochi Prefecture to Matsuno Town in Ehime Prefecture, following National Route 381.
Covering a distance of approximately 90 km, the road winds alongside the Shimanto River, often called “Japan’s last clear stream.”
The route offers a scenic ride through alternating sections of mountain curves and gentle riverside roads, surrounded by rich nature on all sides.
Recommended Riding Section
The most scenic part of the route stretches from Shimanto City (Nakamura) to the area around Ekawasaki Station.
This section hugs the riverbank, offering peaceful curves under dappled sunlight and the calming sound of flowing water.
Please note that some areas are narrow and may require extra caution when passing oncoming vehicles.
Road Conditions and Safety Notes
Most of the route has a road width of around 5 to 6 meters, but certain parts become extremely narrow, especially in the mountains.
Speed limits are generally 40–50 km/h, and visibility can be limited on sharp curves.
While ideal for small and mid-sized bikes, riders should be especially cautious inside tunnels and on narrow passes.
Watch for local traffic and ride with care.
Suggested Stopovers
- Scenic Point: Sada Submersible Bridge – great river views from the roadside
- Iconic Site: Iwami Submersible Bridge – featured in films and a symbol of the Shimanto River
- Roadside Station: Michi-no-Eki Yotte Nishitosa – offers local specialties like Shimanto pork bowl
- Local Cuisine: Try Shimanto eel and deep-fried aonori (seaweed) at riverside eateries
You can find a full list of submersible bridges along Route 381 in this guide (Japanese only).
Costs and Rentals
National Route 381 is toll-free.
Rental motorcycles are available near Nakamura Station in Shimanto City, starting from around ¥6,000/day for 125cc and above. Advance reservations are recommended.
Best Season and Climate
April to June and September to November are ideal for touring.
Spring offers fresh greenery, while autumn provides colorful foliage and morning mist along the river.
In summer, take care to avoid heat exhaustion and be mindful of high road surface temperatures.
Food and Rest Stops
There are riverside spots like Shimanto-ya (a local eatery) and Canoekan Café (a log cabin café), perfect for a relaxing break.
You’ll also find seasonal treats and dishes made from local ingredients.
Touring Plan Examples
- Day Trip: Nakamura Station → Ekawasaki → Iwami Submersible Bridge → Togasaki Viewpoint (approx. 4–5 hours including breaks)
- Overnight Trip: Stay in Shimanto City, enjoy river activities or canoeing the next morning, then continue to Nametoko Gorge in Matsuno Town
Access
Shimanto City is accessible via JR Yodo Line or Tosa Kuroshio Railway. The nearest station is Nakamura Station.
From Kochi City, it takes around 2.5 hours by car. Bus service is also available.
Rental bike shops are located near Nakamura Station.