The flat water spots on this stretch of coast from North to South are: - The Broadwater (NE & SE) - Richmond River, Ballina (SE) - just inside the river mouth - Clarence River, Yamba (NE) - just inside the river mouth behind the rock wall in the river
You could also try some ocean sailing, if you feel confident, from Wategoes Beach, Byron bay in a NEer
PM Ezric, who is a local and sails all these spots, for more info