At about 1.30pm a group of teenage males entered the Waikato River south of the Spa Park thermal hot pools.
The group of twelve decided to enter the river with the intention of floating downstream to the hot pool area.
Shortly after entering the water, one of the group got into difficulties and despite efforts to keep him afloat, friends were unable to save him.
A 17 year old male from Wanganui drowned as a result of the incident.
Wellington Police Dive Squad members have arrived at the scene to recover the body.