A teenage boy was seriously injured when a large wave swept him off the ledge at the Halona Blowhole yesterday afternoon.

The youth was with four or five other teens who made their way down to the blowhole about 12:20 p.m., said Bryan Cheplic, spokesman for the city Emergency Services Department. A large wave crashed onto the rocks, sweeping the boy out, Cheplic said.

The teen's friends threw him a bodyboard and he managed to make his way to Eternity Beach, which is about 100 yards south of the blowhole. Emergency personnel were called and stabilized him at the scene before taking him to a hospital.

Cheplic said the group of teens walked down to the blowhole despite signs warning of the dangers .

"We want to emphasize that people should realize that the Halona lookout is not a place to be swimming," Cheplic said. "Signs are posted and we're asking people to please heed the warning signs and if possible please swim at a guarded beach. Thankfully nobody was critically injured, but this situation could have been a lot worse."

Waves at East O'ahu beaches were near advisory level of 4 to 8 feet at the time of the incident, Cheplic said.

"Even more so, conditions were treacherous," he said.