Lake Toya is one of those rare places where the earth's raw power and serene beauty exist side by side. Formed by a catastrophic volcanic eruption over 100,000 years ago, this near-perfect caldera lake in southwestern Hokkaido has become one of Japan's most beloved summer retreats — and August is arguably its finest month.
While the rest of Japan swelters under oppressive humidity, Toyako Onsen town sits at the southern shore of the lake, cooled by mountain breezes and surrounded by forests that stay green well into autumn. The town is compact, walkable, and built around one simple pleasure: soaking in volcanic hot springs while gazing out at an island-dotted lake that changes color with every passing cloud.
Yakushi no Hi Yukata Matsuri (August 8)
The highlight of Toyako's summer calendar is the Yakushi no Hi Yukata Matsuri, held every year on August 8. The name references Yakushi Nyorai, the Medicine Buddha associated with healing — fitting for a town whose identity revolves around the curative powers of its mineral-rich waters.
On this day, the onsen town transforms into one big open-air party. Visitors and locals alike stroll the lakeside promenade in colorful yukata (light summer kimono), many provided free or at discount by local ryokan and hotels. Street food stalls line the main road offering Hokkaido specialties: grilled scallops from Funka Bay, fresh corn on the cob, melon soft-serve, and the local favorite — Toyako onsen tamago (eggs slow-cooked in hot spring water).
The festival features traditional bon odori dancing on a stage by the lake, taiko drum performances, and a special extended fireworks display that caps off the evening. Unlike the regular nightly fireworks (more on those below), the Yakushi no Hi fireworks are longer and more elaborate, with fireworks launched from boats positioned across the lake for a panoramic effect. Many festival-goers reserve lakeside rooms months in advance specifically for this night, watching the show from their room's private onsen bath.
The Legendary Long-Run Fireworks
Even without the festival, Toyako Onsen offers something almost no other place in Japan can match: nightly fireworks from late April through late October. For roughly 20 minutes each evening (starting around 8:45 PM), fireworks bloom over the lake's dark waters, their reflections doubling the spectacle. Launched from a boat that moves slowly across the lake, the display creates an intimate, almost private show — nothing like the massive, crowded hanabi taikai of Tokyo or Osaka.
The best viewing spots are along the lakeside promenade between the bus terminal and Toyako Onsen pier, or from any lake-facing hotel room. Many visitors time their evening onsen soak to coincide with the show, creating a uniquely Japanese experience: sitting in steaming outdoor baths as colors explode across the sky.
Usu Volcano & the Living Geopark
Toyako's volcanic heritage is not just ancient history — it's ongoing. Mount Usu, which looms over the lake's southern shore, last erupted in the year 2000, and the scars are still visible and visitable. The Toya Caldera and Usu Volcano UNESCO Global Geopark is one of the most accessible volcanic landscapes in the world.
Take the Usu Ropeway from the base to the summit observation deck for sweeping views of the lake, the Showa-Shinzan lava dome (a mountain that literally didn't exist before 1943), and on clear days, the Pacific Ocean. From the top, walking trails lead to crater viewpoints where you can peer into steaming vents and see the raw aftermath of the 2000 eruption: buildings half-buried in volcanic debris, roads buckled and split, all left in place as a powerful open-air museum.
The Nishiyama Crater Trail on Usu's western flank is free to walk and takes about an hour. Elevated boardwalks guide you past craters, displaced infrastructure, and regenerating forest — a sobering and fascinating lesson in nature's power and resilience.
Summer Activities on and Around the Lake
Beyond onsen and volcanoes, Lake Toya offers plenty to fill a summer day. Sightseeing boats depart regularly from the Toyako Onsen pier, circling Nakajima (the forested island at the lake's center) where you can disembark to walk nature trails and visit a small forest museum. Kayak and canoe rentals are available for those who want to explore the shoreline at their own pace.
Cycling the lake is a popular summer activity — the 36-kilometer circuit is mostly flat and follows quiet roads through farms, forests, and small fishing communities. Rental bicycles (including e-bikes) are available near the bus terminal. The western shore is particularly scenic, with fewer tourists and views of Usu's volcanic slopes reflected in calm waters.
For art lovers, the Toyako Manga Anime Festa sculptures are scattered along the lakeside promenade year-round — over 50 bronze statues of beloved manga characters placed as part of a long-running public art project. It's a quirky counterpoint to the area's natural grandeur.
Onsen: The Heart of It All
Toyako Onsen's waters are sodium chloride springs heated by volcanic activity, known for improving circulation, soothing muscle pain, and softening skin. Most hotels and ryokan have both indoor and outdoor baths, many with direct lake views. Several free foot baths (ashiyu) dot the promenade for those just passing through.
For a more adventurous soak, visit the Toyako Onsen public bathhouse near the pier, which offers no-frills, affordable bathing in the same mineral waters the luxury hotels use. Or seek out the smaller, lesser-known baths in Sobetsu Onsen on the lake's eastern shore, where the atmosphere is quieter and the prices lower.
Getting There
From Sapporo, the most convenient route is a highway bus from Sapporo Station directly to Toyako Onsen (about 2 hours 45 minutes, around 2,800 yen one-way). Alternatively, take the JR limited express to Toya Station (about 1 hour 50 minutes, covered by Japan Rail Pass) and then a local bus to Toyako Onsen (20 minutes).
From New Chitose Airport, direct highway buses run seasonally in summer, taking approximately 2 hours 30 minutes.
Tips for Your Visit
• Book early for August 8: The Yakushi no Hi festival night fills up fast. Reserve lakeside accommodation at least two months ahead. • Bring layers: Even in August, Hokkaido evenings can dip below 20°C. A light jacket is essential for the fireworks. • Rent an e-bike: The lake circuit is gorgeous but 36 km is a long ride in summer heat. E-bikes make it effortless. • Visit Usu early: The ropeway gets busy by midday. Go in the morning for clear views and thinner crowds. • Try the onsen tamago: Available at several spots along the promenade, these slow-cooked eggs are a Toyako signature.
Lake Toya rewards travelers who slow down. Spend at least two nights: one for the fireworks and onsen, one for the geopark and lake. In a country where summer often means crowds and heat, Toyako offers something increasingly rare — cool air, hot water, and all the time in the world.
Image: Lake Toya, Toyako, Hokkaido, CC BY 2.5, by 663highland, via Wikimedia Commons
