The boat ramp at Lake King William is located at Butlers Gorge on the southern end of the lake, owned by Parks and Wildlife Service and situated in Tasmania's West Coast region. It is a single-lane concrete ramp and a 4WD vehicle is recommended for access.

This ramp is useable at most water levels, making it more reliable than the launching areas at the lake's northern end off the Lyell Highway, which are subject to the lake's highly variable water levels.

Boaters should be aware that launching is prohibited within 100 metres upstream of Clark Dam, as marked by signs on both banks.

Minimal-impact boating practices are encouraged — accelerate gently in shallow water to avoid stirring up silt and mud, which can cloud the water and degrade fish habitat.