Shiretoko gets the headlines — brown bears, drift ice, a UNESCO stamp. But drive an hour or two before you reach that peninsula, and you pass through a national park that gets a fraction of the attention for reasons that have nothing to do with how good it is: Akan–Mashu National Park, a stretch of caldera lakes sitting quietly between Kushiro and Shiretoko in Hokkaido's wild east.
This is volcano country. Three calderas — Mashu, Kussharo and Akan — sit in a rough line, each one a collapsed magma chamber now filled with water, and each one different enough from the others that "lake" barely covers it as a category. If Shiretoko is the wildlife headline of eastern Hokkaido, Akan–Mashu is the geology headline — and it happens to sit directly on the route between the crane marshes of Kushiro and the bear country further north.
That location is exactly why it gets overlooked. Travelers plan around Shiretoko, or around Kushiro's cranes, and Akan–Mashu ends up as the thing they drive through rather than the thing they came for. It deserves better than a bathroom-break stop between two more famous destinations.
Lake Mashu: the blue that doesn't look real
Start with Lake Mashu, and start with the color, because that's the whole story. This is a lake known for a blue so clear and so improbable that it's routinely described as impossible — water that looks less like a lake and more like something lit from underneath. And you experience it the way the caldera insists on: from above, at a rim viewpoint looking down onto the water, rather than from a shoreline or a boat. It's a lake you look at, not one you walk into — closer, in that sense, to standing at the edge of a canyon than visiting a lake in the usual way. Give it unhurried time at the rim rather than treating it as a five-minute photo stop; the view is the entire destination here, not a bonus on the way to somewhere else.
Lake Kussharo: the caldera you can soak in
Where Mashu keeps its distance, Lake Kussharo invites you in. It's the other great lake of this national park, and it plays a completely different role: its shores are lined with hot-spring bathing spots, so you can sit in the water and look straight out at the lake itself. In winter, swans gather along its shores — one of the signature images of this whole caldera region.
Between the two lakes rises Mt. Io, a sulfurous peak — the visible reminder that this entire landscape is volcanic country, and that the calderas holding Mashu and Kussharo are craters, not just scenery.
Lake Akan: the third corner of the caldera
Round out the trio with Lake Akan itself, on the western edge of the park. It belongs to the same volcanic family as Mashu and Kussharo — another caldera lake completing the geological set — and for travelers moving through on the Kushiro–Shiretoko corridor, it's worth knowing it's there even if Mashu and Kussharo are the two that will eat most of your time on a short pass through. If Akan becomes its own stop on a future trip, it deserves a dedicated look rather than a rushed half-day tacked onto the end of this one.
Base yourself in Teshikaga
The obvious base for all of this is Teshikaga, the caldera town between Mashu and Kussharo. It doesn't try to be more than what the geography gives it — this is caldera country, full stop, built around Mashu's impossible blue on one side and Kussharo's onsen shoreline on the other, with Mt. Io in between. Stay a night here and both lakes are within easy reach, which is the whole logistical case for the town: nobody visits Akan–Mashu and skips Teshikaga.
Combining it with Shiretoko and Kushiro
Akan–Mashu rarely stands alone in a trip plan, and it shouldn't — its real strength is the corridor it sits in. Coming from Kushiro, home to Japan's largest wetland and its red-crowned cranes, Teshikaga is roughly the next stop east before the road turns north toward Shiretoko, Hokkaido's UNESCO-listed bear country. Coming the other direction, off the Shiretoko peninsula, Akan–Mashu is the natural way to unwind out of bear country and back toward Kushiro's airport — a caldera interlude between wetland and wilderness.
Either direction, the logic is the same: this is what a Hokkaido road trip east of Kushiro actually looks like on the ground — wetland, then caldera, then peninsula, in whichever order your flights dictate. Few FIT itineraries reach this far east at all, which is exactly why the ones that do tend to remember it as the best few days of the trip.
Our own 10-day itinerary runs exactly this shape: a day at the Shiretoko gateway, then Teshikaga and Kushiro back to back before heading west again. It's not the only way to sequence it, but it shows how naturally these three destinations chain together. We're also building a dedicated guide to this whole stretch — Eastern Hokkaido: the wild east — if you want the fuller regional picture beyond this one park.
If you'd rather build the sequencing yourself, our trip planner is preloaded for a nature-and-wildlife, ten-day summer route and will let you slot Akan–Mashu in wherever it fits your own pace — whether that's a single overnight in Teshikaga or a longer caldera-focused loop.
When to come
June–September is the easiest window: the Kussharo onsen are pleasant rather than punishing, the roads through the park are all open, and you've got the best odds of a clear window at Mashu's rim. Winter brings its own case — Kussharo's shoreline steams against the cold and the resident swans are at their most photogenic — but expect a harder drive and shorter daylight to work with.
Whatever the season, treat Mashu's viewpoint as a moment rather than a milestone, and give Kussharo the hour in the water it's asking for. This is quieter, slower country than Shiretoko, and it rewards exactly that pace. Feed the shape of it into the planner and let it hold the caldera's place in your route from Kushiro all the way to the wild east.
Northern Land Hokkaido Team — Sapporo, Japan