The 14-year-old became trapped in the purifier of his local pool and was unable to free himself because of the force of the suction.
Teenager was left fighting for his life after his intestines were sucked out by the filter of a swimming pool
His intestines were then horrifically sucked out, causing him serious injuries and requiring a life-saving operation.
The boy was enjoying a swim in the pool of a private leisure centre in Carpesa, Valencia when the accident happened at 9.30pm.
The emergency services rushed to the scene and freed the youngster who was then taken to hospital.
He underwent a four-hour life-saving operation in La Fe hospital in Valencia and is still in the intensive care unit.
It is understood he is now out of danger.
The boy had been attending swimming lessons and according to witnesses, he and some of the other children had stayed behind afterwards to play in the water.
It is thought the youngsters lifted the purifying vents off and then sat on them.
A trainer on the scene turned hero by jumping into the water to save the boy, whilst ordering the mechanism to be switched off.