The Hirabo area is located in Kihoku town, Kanoya city. The water and the air are very clear there and there are some different kinds of wild fireflies in this area.
Going after 19:00 is recommended, because the fireflies start to fly around this time.

[Hirabo Hotaru Festival]
Date: May 23 (Sat) ~ June 6 (Sat)
During the period, you can check the approximate numbers of fireflies at the address below.
http://blogs.yahoo.co.jp/hirabouhotarunosato

Good season to watch: The end of May ~ the start of June
Location: Drive up on Route 504 and turn right at Kanoya City Hall, Kihoku Branch on to Prefectural Route 72. About 5 minutes’ drive after that.