I did not see any nets at Yohana beach, but we also did not see any jelly fish. I also swam in several areas with no problems.

The only way to get to the island is by airplane. Are you talking about the mainland Japan right? If so,there is only one direct flight per day from Tokyo Haneda by JTA; his parent comany is JAL Oneworld. One way ticket would be like $ 200-300 USD but good news is that If you are a non Japanese resident, and entering Japan as a tourist, you can use JAL yokoso Japan pass and it will only cost 120$ from Tokyo but it has to be a direct flight and you gotta take Oneworld flight to go to Japan. If you are taking Staralliance, there is a similar offer by ANA called Explore Japan Pass but there is no flight to Miyako directly. only to Ishigaki or Okinawa. if you are taking non of those airlines and still want to save some bucks, you can take jetstar, peach, vanila airlines from either Tokyo, Osaka to Okinawa or Ishigaki, then take JAL or ANA from Ishigaki or Okinawa. Personally, if you have no particular reason to go to Miyako Island from the mainland,I would just recommend to go to Ishigaki island and take a boat to smaller islands near by. Its as beautiful as Miyako island and Ishigaki island has a lot of things to offer and there are more flights from Tokyo and Osaka as well.