Filmed at a swimming pool in Helsinki, Finland, shows the young boy splashing about frantically, struggling to stay above water.
He continues to wave his arms in the air, desperately trying to keep himself afloat, as other children and adults swim by.
After several minutes, the boy can no longer keep up the fight.
His body is seen floating in the water as parents with children continue to pass by in the harrowing footage.
Eventually, a woman goes to check on the boy, realises he is not responding and quickly carries him out of the pool.
He was rushed to a nearby children’s hospital and miraculously made a full recovery.
According to court documents, the boy’s mother had left him unattended to enter a spa at the swimming pool.
She had told him to stay in the children’s pool, but the five-year-old had wandered into the adult area and soon found himself out of his depth.
It is believed the boy may have been submerged for four-and-a-half minutes.
Helsinki District Court sentenced the boy’s 44-year-old mother to a suspended four-month prison sentence and ordered her to pay €1,500 (£1,300) in compensation.