Kamuiwakka River is a naturally hot river in the wilderness of the Shiretoko Peninsula, known for its hot waterfalls (カムイワッカ湯の滝, Kamuiwakka-yu-no-taki, lit. "Kamuiwakka Hot Waterfall"). It is possible for tourists to hike up the hot river, which makes for one of the best hot spring-related outdoor activities in all of Japan.
From 2006 to 2022, visitors to Kamuiwakka River were able to walk up only a 140 meter long lower section of the river due to the danger of falling rocks and to reduce the impact of tourism on the environment; however, in 2023, a 500 meter long section of the river was reopened to tourists under a new system, which limits the number of visitors and requires advance reservations and an admission fee. See more details about the admission system below.
The hike up the river takes about 30-45 minutes one way and involves climbing three waterfalls before reaching the fourth waterfall at the end of the trail. The water increases in temperature from lukewarm at the trailhead to around 38 degrees Celsius (100 degrees Fahrenheit) at the fourth waterfall, above which steaming hot spring sources can be seen. Because the water is highly acidic, the riverbed remains free of slippery plants, and it is recommended to walk up the river in the water rather than along the more slippery edge of the river.
Climbing the three waterfalls is not easy and requires a certain level of agility. Especially the third waterfall is steep and tall, and falls can result in nasty injuries. Consequently, all visitors to Kamuiwakka River need to watch a preparatory video before their visit and bring proper equipment. Helmets are mandatory and provided for free at the trailhead. Aqua shoes are recommended for climbing the river and are available for rent in limited numbers at the Shiretoko Nature Center (8:00 to 17:30, 1100 yen/day).
Expect to get wet at least to the knees. Some visitors come in bathing suits and enjoy a bath in one of the natural pools found along the river. Note, however, that the large pool, which used to exist at the base of the fourth waterfall before the 2005 closure, was destroyed by falling rocks and cannot be used anymore.
A ten kilometer dirt road connects the Shiretoko Five Lakes with the trailhead of the Kamuiwakka River. It is open only from early summer until late autumn.
By car or motorcycle
In 2023, access to the trailhead is possible from June 1 until October 2, except from July 22 to August 19 when the road is closed to cars and motorcycles between the Shiretoko Five Lakes and the trailhead, and shuttle buses are running instead.
Shuttle buses operate between the Shiretoko Nature Center and the trailhead of the the Kamuiwakka River from July 22 to August 19, 2023. The journey takes about 45 minutes. The fare is paid together with the admission ticket to the river (for a total of 2800 yen per person) or is 1300 yen for a round trip for those not entering the river. There is no public transportation during the rest of the year.
By bicycle or on foot
In 2023, the ten kilometer road between the Shiretoko Five Lakes and the trailhead can be used by cyclists and pedestrians from June 1 until October 2. The average pedestrian will require 2-3 hours one way to reach the trailhead from the Shiretoko Five Lakes.
The season for visiting Kamuiwakka River is limited to just a few months in summer and early autumn (July 1 to October 1, 2023). Advance reservations need to be made online for a specific date and time slot. They can be made on the day if space is available. The admission fee is 2000 yen per person and needs to be paid when making the reservation.