For the best hikes in Japan, visit its northernmost island, Hokkaido, which boasts six national parks. From the island's main city, Sapporo, take a cable car to the top of Mount Moiwa and admire the panorama, or explore Odori Park in central Sapporo, which is reminiscent of Central Park in New York. The island is bursting with beautiful natural parks, like in the five lakes region in Shiretoko, where you can observe wild animals.
Behold several wonders of nature here, including the Kamuiwakka hot waterfall and the Furepene falls, created by the melting snow and ice from the mountains. You can reach it by hiking into the center of Shiretoko. With some luck, you may even get the chance to see the aurora borealis.
After this active day, you'll be in the mood for some relaxation. There's nothing better for that than the onsen thermal springs. Soak in Yunokawa springs, or visit Lake Akana to unwind in the onsen there.