It is a small island, but you still need a car if you want to enjoy the beautiful scenery.
The water is very clear. You can see fish from above the surface of the water.
If you want to enjoy a short kayak tour, one is available at Fukido river which is just south of Nosoko town, and another is at Miyara river which is a few miles away from the airport. I was taking photos, so my husband was paddling the whole time (^^)
English language tours are available but their website is in Japanese only, at Orion Ishigakijima Eco Tour Service . This site is only in Japanese, but you can translate it with Google Translation to get a general idea and the contact information. For translation to English go to https://translate.google.co.jp/translate?hl=ja?sl=ja&tl=en&u=http%3A//orionza.jp .
I don’t know if you would like the cave with a lot of colorful lights, but still it is an amazing place.