Iwanai-dake and Raiden-yama Hiking


Posted on Apr 20, 2020

Posted on Apr 20, 2020

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Highest point



Best season icon (Hokkaido Wilds)

Best season

Iwanai-dake 岩内岳 (1085m) stands at the western end of the Niseko Range, rising steeply above the coastal town of Iwanai. Although the climb follows a partly abandoned ski slope with derelict lifts for some of the way, the rocky summit rewards you with a spectacular bird’s-eye view of the coast and along the length of the range to Annupuri. Fit hikers can continue on for a few more hours and traverse to the nearby mountains of Mekunnai-dake 目国内岳 (1220m) to the east or, as described here, Raiden-yama 雷電山 (1211m) to the west for a satisfying long day out in this quiet part of the Niseko hills.

We visited this route on Oct 27, 2019

Last updated Apr 22, 2020

Route Map

Need to know details


Iwanai-dake is above the port town of Iwanai 岩内町on the Japan Sea coast of Hokkaido, northwest of the Kutchan-Niseko ski area. This hiking route up Iwanai-dake starts just before the Iwanai Marine View campground carpark, around here.

General notes

Although this route describes the traverse all the way to Raiden-yama, Iwanai-dake is a satisfying climb in its own right if time and/or conditions do not permit or you just fancy a shorter day. The Marine View campsite (here) is conveniently located right next to the trailhead. The summer hiking season is from June into November.

Route Timing
Up | 3hrs
Down | 2hrs

The above times are for Iwanai-dake only, expect to take up to another 3 hours if extending to Raiden-yama or Mekunnai-dake.


The trail is well defined with signposts at junctions. From the trailhead at 200m elevation (here) climb up through scrubby trees and bushes to emerge at some derelict ski lifts (in 2019 the machinery was still in place though abandoned). Another slightly overgrown trail that starts from the foot of the ski slope proper merges from the left. From here you climb up more steeply through forest, past the abandoned top station of another old lift at about halfway, then up through forest and shrub to an open shoulder and the final slopes to the rocky summit in less than three hours total. To extend the walk to Raiden-yama or the rocky tor of Mekunnai-dake, continue on over the summit and down to a signposted junction in about 15 mins. Turn left for Mekunnai 目国内岳 (about 2 hrs 20 mins return) and right for Raiden 雷電山. The path from here undulates through head high sasa dwarf bamboo, over some minor summits and past a marshy area to reach the flat summit of Raiden-yama in two hours or less. Return the same way.


Public transport:

Public buses run from Iwanai Bus Terminal (here) to Ikoi no Yu いこいの湯 onsen (here) about 15 mins walk from the trailhead, though a taxi would be far more convenient.

By car: 

From Iwanai town centre follow signs south up to the ski slope スキー場. Just before you reach the main buildings at the foot of the slopes turn right at the sign for the trailhead 岩内岳登山口 next to a large sign for the Marine View campsite. A hundred meters or so up the road another sign directs you into a parking area.



Physical maps

Yama to Kogen Chizu 山と高原地図, No.2 Niseko Yoteizan ニセコ・羊蹄山. Published by Shobunsha 昭文社. 1:50000 hiking map in Japanese with marked routes and course times.

GSI Topo Map: Iwanai (岩内) – map no. NK-54-20-7-3
GSI Topo Map 2: Raiden-yama (雷電山) – map no. NK-54-20-11-2

NOTE: The GSI 1/25000 topo map(s) above can be purchased for 350yen each from Kinokuniya bookstore next to Sapporo Station or online (in Japanese).

route safety

The upper slopes and summit are exposed to the wind off the ocean and the appropriate bad weather gear should be taken. The usual bear precautions should be followed.

Weather forecast

Windy.com weather forecast for Iwanai-dake

Onsen nearby

There are a couple of cheap and cheerful onsen facilities just down the road from the trailhead. We liked the smaller lower one (Sansan no Yu, サンサンの湯, location, 500yen) – no outside bath and scalding hot but a friendly owner and even more friendly dogs.

Extra Resources

In Japanese: Hokkaido Natsuyama Gaido 1, 北海道夏山ガイド 1 道央の山々 (Hokkaido Shimbunsha), pp.298-309. These guides are updated every few years.

Guide Options

If you’d like to hike this route and/or explore other areas of central Hokkaido with a local certified guide, then contact Jun Ishiguro. He’s a JMGA (Japan Mountain Guides Association) mountain guide on the board of directors of the Hokkaido Mountain Guides Association (HMGA). As a senior figure in the Hokkaido guiding scene, and with extensive experience, he can tailor trips to your needs. See a full list of English-speaking Hokkaido Mountain Guides Association (HMGA) guides on the HMGA website here

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Route Trip Notes

Now that the expressway has been extended past Yoichi it is much easier to get to the Niseko hills from Sapporo, so Jeff and I headed out early one morning in late October. Perhaps it was the early hour, but for some reason we managed to miss the obvious sign to the official trailhead and parked below the ski slope buildings a couple of hundred meters further on. After a false start we located an overgrown track leading up beside an abandoned lift, which joined up with the main trail after about 20 minutes. Jeff noticed some yamabudo wild mountain grapes growing beside the path so we made a note to get some on the way back.

From here it was a steady climb up, passing at one point under another abandoned ski lift terminus, slightly ghostly in the low light. Further up the hill the views behind opened up to the town and the bleak sweep of coastline around to the nuclear power station at Tomari. A cold wind was blowing on the final unsheltered slopes so we hurried on to the summit. After enjoying the view down to the town beneath our feet we dropped down the other side to a different landscape of rolling hills covered in sasa dwarf bamboo. At the junction we decided to go right to Raiden-yama.

It was probably not the best day for it. The path cut like a trench through head high sasa bamboo over gently rolling hills, limiting the views. This was not helped by mist rolling in as we got nearer to Raiden. At one point there was a partly inundated marshy area where I could show off to Jeff my bog hopping skills, perfected by many years walking in the notorious peat hags of the Peak District in northern England. After a short traverse that would have given good views if there had been no mist, we were among the sasa and haimatsu dwarf pines at the flat summit of Raiden-yama. Nothing to see. We turned around.

The cloud had lifted by the time we got back to Iwanai-dake, so we stopped there out of the wind behind the summit rocks to boil some water for some warming instant noodles before descending. Back at the old ski lifts we couldn’t resist exploring, treading carefully on the rotting structures. Nature was steadily reclaiming them. On one lift station a flowering vine had coiled its way around an abandoned seat. Jeff’s inner ski bum drew him into the wrecked operator’s booth where he pressed the buttons with glee (he did grow up in a ski town in Oregon after all.) Fun over, we headed down the path a few more minutes to where we had seen the wild grapes. We tasted a few – deliciously sharp and bursting with grapey fruitiness. Jeff whipped out a plastic bag, and suddenly we realized that they were everywhere around us. Unusual, since the bears love them. We filled the bag to overflowing but didn’t even make a dent in their number.

Finally back at the trailhead, we pulled off our boots and headed to the onsen just down the road, noting the sign to the trailhead that we had missed on the way up. Only the smaller lower building was open. The owner looked at us with a slightly worried expression. ‘It’s very hot,’ he said. ‘No problem,’ we replied. It was hot. One of those baths where you lower yourself in gently then don’t dare move a muscle for as long as you can stand it. There were a couple of locals there, one elderly gentleman sporting extensive yakuza tattoos. He didn’t seem to mind us though. Jeff emerged looking partly boiled and had to slump in the corner to recover. While waiting for him to appear I got chatting to the owner and made friends with his lovely dogs. I admired some of his winter photos on the wall and he showed me some more as Jeff joined us. After a few minutes more pleasant conversation we set off back to Sapporo. Although the weather hadn’t been great it had been a real off the beaten track day out, local Hokkaido at its best.

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Iwanai-dake and Raiden-yama Hiking Difficulty Rating





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GRADES range from A (very difficult) to D (easy). Hazards include exposure to avalanche and fall risk. More details here. Rating rubric adapted from Hokkaido Yukiyama Guidebook 北海道雪山ガイド.