St Clair Surf Life Saving Club members Aidan MacRae (13) and Chris MacDonald (15) were swimming back to St Clair Beach after training when they were brushed by what they say was a shark 2m long.
As the pair were swimming back to St Clair, Aidan started to feel tired and cold - that was when the shark brushed past Chris.
''We were slowing down and I kept looking back to check on him and that's when I felt something rub on the inside of my right leg,'' Chris said.
Aidan said once he saw the shark he panicked and could not communicate with Chris.
''I couldn't speak properly and I was trying to tell him to go back to Second [Beach] but he couldn't understand what I was saying.''
Once over the initial shock, Chris started to call for help.
''I just started waving and yelling, hoping someone could see us and get help.''
Someone on shore heard his calls and called the police - that was when the boys tried to swim back to Second Beach.
But by that stage Aidan was too tired to swim and was not able to keep his head above the water any longer, so Chris held him up as they swam to some nearby rocks.
''I pretty much stripped off his wetsuit because he seemed hypothermic and we waited for people to come and get us,'' Chris said.
Police, St John and fire crew from the St Kilda station were all called to the beach.
Members of the surf club also paddled around to where the pair were standing.
Aidan was assessed by paramedics before they both had a hot shower.
Despite the close call, the pair will be back training in the water today.
