No opening hours or admission are shown: the sources we checked on 2026-09-13 were used for the route only. Check the official site
Our guide
Lake Mashū, Kamuy-to in Ainu, is a crater lake with no outflowing river, in the caldera of a potentially active volcano within Akan-Mashū National Park, Hokkaido. It has been called the clearest lake in the world.
One thing to know before you go: our checked record notes that fog often hides the lake in July and August. It also says the JR Senmō Line (Kushiro–Abashiri) serves Mashū Station, the town's only staffed station, with buses and taxis, and that the First Observatory — the most popular viewpoint — is the first you reach coming from Teshikaga. The details are in “Plan your visit” below.
Written by japan-spots.com (2026-09-22) from the sources credited on this page. Distances are straight lines between map positions.
Photos
Photos from Wikimedia Commons, each under its own licence — see credits
- Hokkaido, Japan, Lake Mashū, 2008 — Miya.m · CC BY-SA 3.0 · source · resized
- 1974 Japan Lake Masshu — Roger McLassus 1951 · CC BY-SA 3.0 · source · resized
- Lake Mashu — 通 · CC BY-SA 3.0 · source · resized
- 摩周湖 Lake Mashu - panoramio — lienyuan lee · CC BY 3.0 · source · resized
- Lake Mashū Japan during wintertime in Akan National Park Hokkaidō — Kpravin2 · CC BY-SA 4.0 · source · resized
- Lake Mashū 20200222 — Suicasmo · CC BY-SA 4.0 · source · resized
- Lake Mashū 20200222-2 — Suicasmo · CC BY-SA 4.0 · source · resized
- Lake Mashū 20200222-3 — Suicasmo · CC BY-SA 4.0 · source · resized
- Lake Mashū 20200222-4 — Suicasmo · CC BY-SA 4.0 · source · resized
- Lake Mashū 20200222-5 — Suicasmo · CC BY-SA 4.0 · source · resized
What this place is
Lake Mashū (摩周湖, Mashū-ko) (Ainu: Kamuy-to) is an endorheic crater lake formed in the caldera of a potentially active volcano. It is located in Akan Mashu National Park on the island of Hokkaido, Japan. It has been called the clearest lake in the world.
Visitor information checked: 2026-09-13 · Teshikaga Navi (Lake Mashū Tourism Association): access · Kawayu Visitor Center: Lake Mashū First Observatory
Background text from Wikipedia (CC BY-SA 4.0)
What to expect at this type of place: Lakes & falls
Getting there by public transport
- By rail, the JR Senmō Line (Kushiro–Abashiri) to Mashū Station — the town’s only staffed station, with bus and taxi connections.
- Kushiro, Memanbetsu and Nakashibetsu airports are each a little over an hour away by car.
- The First Observatory, the most popular viewpoint, is the first one you reach coming from Teshikaga.
- Fog often hides the lake in July and August.
- Parking at the First Observatory is paid in season; the fee office closes from November to April.
Route checked: 2026-09-13 · Teshikaga Navi (Lake Mashū Tourism Association): access · Kawayu Visitor Center: Lake Mashū First Observatory · Timetables change — check the operator before you travel.
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