Ishigaki or Miyakojima?

I’m going on a 2 week trip to Japan with my friends (we are all 18 and have lots of energy). We will be stopping by Okinawa for around 4 days. Since we don’t have much time, I just wanted to pick one small island that is relaxed. I do not want to worry too much about logistics. We are interested in these activities: relaxing at the beach, stargazing, jetskiing, snorkeling, scuba diving, and just exploring beautiful beaches and going on quick little shallow snorkel trips right off the coast. However, i am also fine with being relaxed and not doing too much, as we will be doing lots of things in Tokyo, so this will serve as like a “reset” in our trip. I also would appreciate it if there wasn’t many other tourists. I’m fine with renting a car, but we may just uber around if that’s viable. Out of Ishigaki and Miyakojima, which one should we choose?

by TigerLocal