Onneto Lake and Onnebetsu River

根室温根沼 | Onne-to

Posted on Aug 26, 2020

Posted on Aug 26, 2020

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0.5 day(s)





Water clarity




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CAUTION: Check the tides for this route carefully before setting out. Putting in about two hours ahead of high tide will reduce the likelihood of getting stranded.

Onnebetsu River (温根別川) flows into the shallow tidal Onneto Lake (温根沼), surrounded by ancient Sakhalin spruce forests. Often shrouded in moody coastal fog, the quiet groves next to the lake and river are draped with moss. White-tailed eagles watch paddlers with a nonchalant caution, while boisterous red-crested cranes pick at the shallows on the lake-edge. This route requires some careful consultation with the tides, but rewards with one of the more varied paddling routes in the area.

We visited this route on Jul 21, 2020


Route Map

Need to know details

Lake Details

This route is on Onneto Lake (Nemuro) (根室温根沼), or Onne-to in the Ainu indigenous language. The lake is a natural lake, about 1.7km wide and 6km long. It has a shoreline of 15km and a maximum depth of 7.3m (1m average). The lake is at 0m above sea level.


Onnebetsu River flows into Onneto Lake just west of Nemuro City in far-eastern Hokkaido.

Put-in Location: Google Maps

Put in at the one-lane concrete bridge over the Nishi-rokuban-sawa River (西6番沢川). There’s a small turning bay a bit further on from the bridge with enough room for two cars to park. Note that the forestry road to the put in is a bit overgrown in parts, and there’s limited mobile phone coverage in the area – we recommend downloading maps in advance to find your way.

Take-out Location: Google Maps

Take out just before Onneto-ohashi Bridge (温根沼大橋) on the right side of the channel. There’s a nice pebbly beach to pull up on, and a high-tension powerline tower where canoes can be stashed behind for the shuttle. Take care when crossing the main channel, particularly at the change of tides – we clocked almost 10km/h without paddling in the middle of it, quite the tidal current.

General notes

We’d not expected this route to be anything particularly special, but it turned out being one of our favourites in the far eastern marshlands in Hokkaido. The bicycle shuttle along the gravel road through the Sakhalin spruce forest, covered in moss both on the trees and on the forest floor, was breathtaking. The view of the forest from the water was equally as gorgeous, with the added bonus of a variety of bird life. This route is, arguably, its best in dense fog. While the fog makes the final channel crossing rather nerve-wracking (make sure you’ve got your maps pre-loaded for GPS navigation), the forest is quite breathtaking as it slowly unfolds out of the mist.

  • Tides: This is very much a high-tide only route. The put-in we’ve indicated here becomes impossible in low tide, as does much of the lake-shore paddling. Check the Nemuro tides here and ideally be on the water a couple of hours ahead of high tide to be on the safe side.
  • Midges: We’ve never seen so many no-see-um midges in Hokkaido than at the put-in of this route. Cover up well, and use plenty of insect repellent. Once on the water we were fine.
Route description

The put-in is a bit awkward, requiring a bit of grass-whacking, but once on the water, paddle downstream on the minor creek to the main Onnebetsu River. The paddle upstream to the road-closed bridge was pleasant, and we’d probably do it again – you get up close to the beautiful Sakhalin spruce forests. Turn around at the bridge, and head downstream. If you’ve timed things well for anything other than low tide, you’ll have your pick of route north along the lake. We hugged the left-hand shoreline, and enjoyed close encounters with eagles, red-crested cranes, and diving ducks. At about 8.5km on the GPS track, start a long diagonal traverse across the main channel. At about two hours shy of low tide, the out-flow was strong enough that we’d be very wary of crossing the channel at right-angles. Capsizing in that channel would likely result in a very long swim, mostly with the current, into the fishing port beyond the bridge.

Route Timing
Trip time: 3hrs 0min

The majority of this route is flat-water paddling, so it’s best to allow about three hours, including time to sit and watch the wildlife along the way.


Public transport:

The put-in is not accessible by public transport.

By car: 

There’s room at the take-out for a couple of cars, on the Nemuro side of Onneto-ohashi Bridge, here. There’s less room at the put-in, but there is a small turn-around bay on a bend in the gravel forestry road suitable for a couple of cars just beyond the concrete bridge, here. As mentioned above, the forestry road to the put in is rough and a bit overgrown in places.

Physical maps
Official Topo Map: Ochiishi (落石) – map no. NK-55-26-5-4
Official Topo Map 2: Nemuronanbu (根室南部) – map no. NK-55-26-5-3
Official Topo Map 3: Tobai (東梅) – map no. NK-55-26-9-1

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

route safety

The main concern for this route is timing the tides. Getting suck half-way at low tide will greatly complicate access to the take-out point, and may require paddlers to paddle the channel out to the fishing port (i.e., into the sea). Only attempt the route with plenty of high-water time under your belt. Also note that while the southern end of the lake, as well as Onnebetsu River is accessible in a couple of places via road, there is next to no traffic on these forestry roads. Paddlers need to be self-sufficient, and preferably carry some means of emergency communication such as a satellite messenger (cellular coverage is patchy at the southern end of the route).

Weather forecast

Windy.com weather forecast for Onneto Lake (Nemuro)


Onsen nearby

If you’re headed back to Nemuro, try the Minato-yu sento (public bath) in Nemuro (みなと湯location, 450yen).

Extra Resources
No extra English resources that we know of. If you know of any, please let us know in the comments.

Guide Options

If you’d like to explore this route with an experienced local guide, contact Masao Ashida from Ashiyan Canoe (https://www.ashiyan-canoe.com). Follow him on Instagram here.

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Show Full Route Notes Close Route Notes

Route Trip Notes

This was our second full day of our ‘workation‘, so to get this route done and dusted by as close to 9am as possible, it was another early 3am wake-up, to be on the water by 5am. First on the agenda was to lock the bikes up at the take-out carpark.

It was a classic Nemuro foggy morning.

Then we headed on to the put-in location along the forestry road. The adventure wagon was in its element.

We’d intended to put in at a bridge over the Onnebetsu River, but about 500m before the bridge, there was a chain across the road, with a sign saying the road was closed due to washouts. This only left one other option, about 1km back along the gravel road to a small bridge over a minor creek. The put in was a bit awkward and steep, down to a muddy creekbed, but we made it happen. The biggest challenge was not being driven mad by the no-see-ums. Haidee was well covered up, including gloves, but my wrists and hands got a beating. It took two weeks before the itchy welts subsided – amazing that such small creatures can cause such discomfort.

Once we were on the water, I was free from the scourge of the no-see-ums, and we were taken aback at the pre-historic feeling of the forest around us. Haidee spotted a rare green pigeon and we spent some time watching it bathed in morning sunlight. 

Once we were at the Onnebetsu River proper, we opted to paddle upstream to the bridge where we were supposed to have put in. The water was mirror-smooth, reflecting the surrounding Sakhalin spruce forests.

At the bridge we turned around. Aware that we were chasing a receding tide, we changed gears into our quick paddle cadence, and started making good headway down the river into the lake. Along the lakeshore, there were eagles, cranes, kingfishers….

As we approached the northern end of the lake, we could really sense the pull of the low tide. As we started across the main channel, buoys were straining towards the sea, pulled taught with a strong current. Even when we were not paddling we were doing 8km/h according to my GPS. We kept the pressure on the paddles and tried to get across as soon as we could. It was foggy, and we hoped there weren’t any fishing boats coming up the channel. Haidee would later remark at a fishing boat roaring by once we’d got off the water. The bow of the boat was high in the air, the fisherman sat at the back. There was no way he’d see a little craft like us in the murk. 

We made it safely across in the end, stashed the canoe, and started the very pleasant 6km bike ride back to the car. All in all a very multi-sport sort of a morning…all before work.

Comments | Queries | Reports

Done this route to Onneto Lake (Nemuro), or other waterways nearby? Thinking of doing it? Please post any feedback, reports, or queries here. Thanks!

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Onneto Lake and Onnebetsu River 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.