This is an observatory with nature where you can see Ago Bay which has beautiful Rias coastline, and impressive Pacific ocean.
Ago Bay has complex coastlines and many islands. The view from the observatory is ranked in the top in Iseshima. You can walk enjoying the view because there is a slope from the parking lot in from of the observatory.
On the way to Yokoyama Observatory, there is a facility called Sozo-no-mori Yokoyama, and there is a good place which is held "Yokoyama Cherryblossom Festival" every year. Also, "Yokoyama Visitor Center" tells the attractiveness of Iseshima National Park, and you can enjoy various activities there such as starlit sky observation meeting and walking along in Shima-city.