The little boy was discovered in the Cabo Roig urbanisation pool in Orihuela, Alicante, yesterday. Some are suggesting the boy is as young as three-years-old, while others are reporting that he is as old as six.
It is understood he was on holiday with his family.
Officers reportedly found him "very cold" but were quick to react to the situation.
A woman, believed to be a family member, performed CPR on the child before emergency services arrived.
It's believed that the boy had a faint pulse and was breathing as he was airlifted to hospital.
He was eventually revived and taken to Hospital de Alicante by helicopter.
The Spanish Guardia Civil has described his condition as critical.
The three-year-old was on his holiday with his grandparents in the tourist hotspot when the shocking incident occurred, according to The Leader.
It is unclear how long the boy was in the pool for and if he fell in accidentally or was playing by himself.
The Department of Foreign Affairs has yet to provide any specific details on the case but said it was aware of the incident A spokesperson said: "The Department of Foreign Affairs and Trade stands ready to provide consular assistance to any Irish citizen in distress overseas".