Knysna Lagoon is a large estuarine body of water on South Africa's Garden Route, situated within the unfenced borders of the Garden Route National Park. Though commonly called a lagoon by locals, it is technically an estuary — open to both the ocean and rivers. The water is generally calm and flat, particularly in the mornings, making it well-suited to kayaking and stand-up paddleboarding (SUP) for paddlers of all experience levels, including beginners.

Popular launch points include Leisure Isle and the Old Drift/Red Bridge area. From these access points, paddlers can explore waterways past the Knysna Waterfront, Thesen Islands, The Point, Featherbed Nature Reserve, Brenton-on-Lake, and Belvidere. Kayak hire is available from Quay Four Restaurant at Thesen Island Harbour Town, with a minimum hire period of one hour. Public jetties at Thesen Islands and the Knysna Waterfront allow paddlers to moor and access nearby restaurants. Slipways and access points for private boats are available throughout Knysna, with trailer parks on Leisure Isle and Thesen Island.

The lagoon supports prolific birdlife, including malachite kingfisher, heron, spoonbill, and royal ibis. Numerous small beaches are tucked around the lagoon's shoreline, accessible by paddle. Fishing from a kayak is also common, with grunter, leervis (garrick), and stumpnose among the typical catches near channels and river mouths; a fishing permit is required and available at local tackle shops or the post office.

Weather along the coast can change rapidly — within an hour — which can affect the return paddle, so monitoring forecasts before setting out is important. Wearing a life jacket at all times on the water is strongly advised, along with a hat and sunscreen, particularly during summer. Early mornings offer the calmest water conditions for paddling.

The Knysna Canoe Club, based at the Knysna Yacht Club, runs weekly Tuesday evening time trials at 5:30 pm and welcomes paddlers of all skill levels, including a dedicated group for kids and beginners.