The man's body was found at Southshore Spit, where the swimmer was last seen on Thursday afternoon, police said.
Police launched a search with Coastguard, Surf Life Saving, and a Westpac Rescue Helicopter after the 19-year-old went missing in the water about 3.10pm.
At about 6am on Friday, police received a report that a body had been located at the south bank of Southshore by a member of the public.
Police say the body is believed to be the man who went missing.
Coastguard Sumner said a search was launched for the man on Thursday but conditions were challenging, with overcast weather, poor water visibility, and swells of up to two metres.
The search was suspended and volunteers were stood down last night.
The man's death will be referred to the Coroner, the spokesperson said.
