Lake Wairarapa is a large, shallow lake located south of Featherston in the Wairarapa region of New Zealand's North Island. It forms the centrepiece of the Wairarapa Moana Wetlands, an area that also encompasses Lake Ōnoke, neighbouring wetlands, the Wairarapa Lake Shore Scenic Reserve, and Ōnoke Spit. The lake holds considerable cultural and spiritual significance for local Māori, who have regarded it as a taonga (treasure) for hundreds of years.

The lake's shallow depth means the water carries a high sediment load, giving it a characteristically muddy appearance. Kayaking is a recognised activity on the lake, with established launch points at Lake Domain Reserve, Wairarapa Lake Shore Scenic Reserve, Ōnoke Spit, and Lake Ōnoke. These reserves also offer free camping with toilet facilities, though paddlers will need to bring their own drinking water.

A 5-knot speed limit applies on Lake Wairarapa under Greater Wellington Regional Council bylaws, consistent with Maritime Rules Part 91. This regulation governs all motorised vessel traffic on the lake and is worth noting when assessing conditions alongside other watercraft.

Water quality is generally considered safe for water contact activities, though paddlers should avoid the lake for at least two days following heavy rainfall, as runoff from urban and rural land can temporarily degrade water quality. Lake Ōnoke, which connects to the lake system, carries a specific hazard when its mouth is open to the sea, as strong tidal flows make it dangerous — paddlers should be aware of this when planning routes that extend into that area.

The surrounding wetlands support a wide variety of birdlife, making the area of interest to paddlers who enjoy wildlife observation. The flat terrain around the lake and its position between the Tararua Range and Palliser Bay means the area can be exposed to wind, which is reflected in Lake Ōnoke's popularity as a windsurfing location. Paddlers should factor wind exposure into trip planning, particularly on the open water of the main lake.

Brown trout are present in the lake, particularly around river deltas where tributaries such as the Tauherenikau River enter from the north near Featherston.