There is beach access approx 1km to the north of Tannum Sands Main Beach/Tannum Surf Club onto what locals know as "Second Beach". Walk down this sandy path and turn left once you get onto the beach. Left of the path all the way around to Canoe Point & Boyne River mouth is dogs off-leash areas.
Dogs must be under controlled supervision at all times in off-leash areas and must be on a leash at all other times in public areas
Gladstone Regional Council website has a full list of public areas where dogs are permitted.
In Boyne Island, drive down the end of Wyndham Avenue until you reach Olunda Avenue and there is a car park. You are able to walk you dog off leash to the left of the car park. As you walk left you are heading up towards Lilley's Beach. Be mindful at low tide you will share the beach with vehicles, so keep an eye on your dogs.