Before exploring the environs, you might want to pop into Sounkyo's Daisetsuzan National Park Visitor Center, located across from the ropeway (tel. 01658/9-4400; June-Oct daily 8am-5:30pm, Nov-May Tues-Sun 9am-5pm), with displays on the park's animals, plants, and geological wonders. Unfortunately, displays are in Japanese, though an English-language handout offers rudimentary explanations, a topographical map shows the layout of Daisetsuzan National Park, and a TV shows the park's changes through the seasons. If you plan on hiking, you might ask the staff for recommended trails, as well as a rundown on places where brown bears are often spotted. Entrance to the center is free.
Sounkyo Gorge -- The Sounkyo Gorge is a river valley hemmed in on both sides by rock walls rising almost 150m (500 ft.) and extending some 19km (12 miles). Unfortunately, a major rock slide has closed most of the gorge to sightseers (you used to be able to cycle much of the gorge), but you can still see a small portion by walking 3.2 km (2 miles) from Sounkyo Spa (walk down to the highway and turn right) and keeping to the right when the highway disappears into a tunnel. This will bring you to a parking lot beside the roaring river and a view of two famous waterfalls side by side: the Ginga no Taki (Silver River Falls) and the Ryuusei no Taki (Shooting Star Falls). At the far end of the parking lot is a fence, beyond which you can see the gorge. Bring some drinks or a picnic lunch. There are also buses that travel here from Sounkyo Spa, but they're infrequent (ask the tourist office for a schedule).
Going to the Top of Mount Kurodake -- If you're interested in hiking, or even if you're not, take the cable car directly from Sounkyo Onsen to Mount Kurodake, where you'll be rewarded with sweeping views. The tops of the mountains are really beautiful here, covered with wildflowers and alpine plant life. It would be a shame to come to Sounkyo and not spend a few hours amid its lofty peaks. The trip by cable car takes 7 minutes, with round-trip tickets costing ¥1,750 ($15/£7.50) for adults and ¥900 ($7.50/£3.75) for children. From the cable-car station, walk a few minutes farther up the mountain, where you'll come to a chairlift. The chairlift ride (my favorite part) takes 15 minutes, swinging you past lush forests of fir and birch. Round-trip fare is ¥600 ($5/£2.50) for adults and ¥400 ($3.35/£1.70) for children. Ropeway and lift operating hours vary; in summer it's 6am to 7pm, in winter it's 9am to 4pm (call tel. 01658/5-3031 for more information).
