Macquarie Harbour is a vast saltwater estuary on Tasmania's West Coast, the second largest harbour in Australia at six and a half times the size of Sydney Harbour. The primary access point for paddlers is the town of Strahan, which sits on the harbour's edge and serves as a base for kayaking tours and expeditions. The harbour opens to the Southern Ocean through the famously named and dramatic Hells Gates, a point where paddlers can encounter significant ocean swell and conditions. Crossing the harbour's open expanse is a common undertaking, with direct southerly crossings of approximately 11 kilometers documented. These crossings can be slow going when facing a south-west wind, highlighting the area's exposure. The overall paddling character involves navigating a large, open body of water with direct access to wild, oceanic conditions at its entrance.

Notable routes include paddling from Strahan to destinations like Steadmans Beach and expeditions across the harbour toward Hells Gates. Multi-day expeditions, such as a seven-day Gordon River trip, begin by crossing Macquarie Harbour. The harbour is also used for other motorized water activities, including a world record waterskiing attempt that involved towing 114 skiers across it, indicating the presence of substantial boat traffic which paddlers must be aware of. The surrounding region is part of the Tasmanian Wilderness World Heritage Area, contributing to a rugged and scenic backdrop. Paddlers should be prepared for variable conditions, as the area is known for its wild weather, with large swell and wind being significant factors, especially near the ocean entrance.