How Do You Get to Okunikko and Avoid the Iroha-zaka Jam?
This guide is for visitors who want to reach Okunikko, the highland lake and marsh area above the Iroha-zaka slope in Nikko, Tochigi Prefecture. It covers how to get to Nikko by train, how the buses to Lake Chuzenji work, when the Iroha-zaka road jams, and what the Nikko tourism association suggests for avoiding the worst of it.
We used the Nikko City Tourism Association's travel site and the Nikko National Park leaflet that the Ministry of the Environment's biodiversity site hosts. All pages were read on 2026-10-04. The association's pages are in Japanese, and the traffic advice below is our summary of its 2026 edition.
What Okunikko is
The Nikko National Park leaflet explains that the upper part of the park, above the Iroha-zaka slope, is called Okunikko. It says it takes extra time to reach, but the natural setting is wonderful. The park was designated in 1934, which the leaflet describes as one of the oldest in Japan.
By train
The same leaflet gives two train routes. It says the Kegon super express on the Tobu Nikko Line takes about 1 hour 50 minutes from Asakusa Station in Tokyo to Tobu Nikko Station. It says the trip from Shinjuku Station takes about 2 hours, either on the Utsunomiya Line or on the Tobu Nikko Line by the Nikko super express. It notes that cars can be rented near the station. We did not confirm fares, so use a route planner for current prices.
The tourism association's access page offers a route search from Tokyo, Nagoya and Shin-Osaka stations to Tobu Nikko and Imaichi stations. It links to the websites of JR East, Tobu Railway, JR Central, Tokyo Metro and the Yagan Railway.
By bus to Lake Chuzenji
The association says that on weekdays the bus can reach Lake Chuzenji in about 45 minutes from JR Nikko Station. Buses leave JR Nikko and Tobu Nikko stations normally at 30-minute intervals, and extra trips are added at peak times. An express bus using toll roads also runs. It suggests buying tickets in advance on a phone or buying a pass at the tourist center in Tobu Nikko Station, because the ticket counter queue can be long.
The association offers a bus location search so you can see live running status, including delays from traffic. It says this is a guide only and advises leaving plenty of time.
When the Iroha-zaka road jams
The association says Iroha-zaka is made up of two one-way roads. The Second Iroha-zaka carries traffic up from the Nikko side to Lake Chuzenji. The First Iroha-zaka carries traffic down. Each normally takes about 20 minutes by car. In Golden Week or the autumn leaf season, it says the trip can take up to 3 hours.
It lists the bad periods as Golden Week and weekends in the leaf season, especially from mid-October to early November, and between 09:00 and 15:00. In the leaf season on weekends the jams can last until 17:00, and between 14:00 and 15:00 a trip can take more than 3 hours. It adds that even weekdays at the peak of the colors can jam.
For a smoother trip, the association suggests driving up before 07:00 on weekends and holidays. On weekdays, it says the road is easier after 15:00. It points to a traffic information site that lists temporary parking and recommended routes in the busy season.
Detours
If a long delay is already reported, the association suggests two alternatives. One is to leave the expressway in Gunma Prefecture at Numata and reach Okunikko by the Nippon Romantic Highway. The other is to skip Iroha-zaka and go around by the Kirifuri plateau, then toward Kawamata and the Sanno forest road. It lists sights on these detours, among them Kirifuri Falls, the Seto-ai gorge and Rokuhozawa.
The Konsei Pass road, at 2,024 meters on the Gunma border, is closed in winter. The association says it is closed from late December to about the end of April because of heavy snow.
Cars cannot go everywhere
The national park leaflet says private vehicles are not allowed on the road from Akanuma to Senjugahama Beach, by Odashirogahara and Lake Sainoko, to protect nature. Low-emission hybrid buses have run on this 10-km route since 1993. It says the bus service is usually available from April to November, runs infrequently, and warns that you should not miss the last bus.
What we could not verify, and therefore left out
- Train and bus fares, and the current bus timetable.
- Whether the temporary parking lots near the shrines are open on your date.
- Road closures on the day you travel. Check the traffic site and the prefecture's road information.
Related guides
- When and where can you see the autumn leaves in Okunikko?
- What is Okunikko? Senjogahara, Lake Yunoko and the Ramsar marsh
Sources
All URLs retrieved 2026-10-04.
- Iroha-zaka and Lake Chuzenji traffic, 2026 edition (Nikko City Tourism Association, in Japanese) — (jam times, detours, buses)
- Access (Nikko City Tourism Association, in Japanese) — (route search and operator links)
- Nikko National Park leaflet (Ministry of the Environment, English PDF) — (Okunikko, trains, hybrid bus)