Mt. Fuji is the highest mountain in Japan. The official climbing season of Mt. Fuji is from July 1 to the end of August.
It's refreshing to play at water parks in summer. Here is a list of great water parks in Japan. Most of Japan's outdoor swimming pools open in early July and close in early September. They can be crowded during school summer holidays, from late July to August.
As Japan is surrounded by oceans, you can find beaches in most prefectures. Here is a list of some popular locations.
Camping has become a popular leisure activity among Japanese in recent year and thousands of campgrounds have been built all over the country. If you plan to stay in a campground during the summer (July and August) or on weekends, early reservations are recommended.
There are many summer outdoor concerts planned in Japan, featuring artists from around the world. It's nice to enjoy live music being surrounded by nature. If you go, be prepared for hot weather.
Festivals in Japan are major tourist attractions. Most of fun and exciting festivals are held in summer months.