The boy, part of a tour group from a school in Grahamstown, was trying to rescue a fellow pupil when he was washed out to sea at Kenton main beach, NSRI Port Alfred station commander Juan Pretorius said in a statement.
“A female learner, aged 11, had gotten into difficulty in rip currents and a fellow male learner had reportedly gone into the surf to try to assist her,” he said.
“Unidentified bystanders had then assisted the female learner from the water, but the male learner was missing in the surf.”
The girl was treated on scene and taken to hospital in a serious, but stable condition.
The children, who were from the Archie Mbolekwa Primary School, had been accompanied by teachers while they were swimming.
The police dive unit would continue searching for the boy.
In a separate incident, a schoolgirl was rescued at Silver Beach in Port Edward on Friday, NSRI station commander John Nicholas said.
The 13-year-old, who was part of a group from a school in the Transkei, was swimming when she was swept out to sea. Bystanders rescued her. She was taken to hospital in a serious condition.