These are students in grades four, five, and six from Shimizu Elementary School in Kagoshima City. Every year they breaststroke 4.1km from the volcano Sakurajima across Kinko Bay to Iso Beach, which is near their school. These photos were made as they did their practice swims in preparation for the real swim. I believe they swam 1.5km twice with an hour break in between. They did this both Saturday and Sunday.
The photos were made two different weekends as is evident in the change of lighting. The kids were saying the water was cold on the first weekend, the parents and myself found the heat and humidity almost unbearable the second weekend.