Marine Rescue NSW says lifejackets played a crucial role in the successful rescue of 3 teenage boys from a capsized vessel in Lake Macquarie.

The boys were in a tinny which capsized on the southern side of Wangi Wangi on Monday morning.

Water Police alerted Lake Macquarie Marine Rescue, who arrived on scene with 12 minutes of the call.

By then, the trio had been clinging to the hull of their upturned boat and treading water for about half an hour before being rescued.

They were taken to the Dobell Park boat ramp where they were given the all clear by paramedics.