Good places for a long swim?

Hi. We are visiting Okinawa this week and staying at toya beach in Yomotan. I was hoping to find a good beach to do a longish open water swim. It seems that there are a lot of warnings about the dangerous sea critters here and that these threats are taken seriously. But it seems like most would involve walking in the water and for swimming only the jellyfish seem like a problem. These usually come in groups at somewhat predictable times so presumably there would be warnings if they are around. So would it be crazy to swim outside the nets at say Zanpa beach or Melody beach? Or better yet, are there any groups of swimmers I could join this week? Thank you.