Cantuaria sinclairi is a species of trapdoor spider endemic to New Zealand.

[1] This species was described in 1968 by Ray Forster from female specimens collected in Westland.

The holotype is stored at Otago Museum.

[1] This species is only known from Moana in Westland, New Zealand.

[1] Under the New Zealand Threat Classification System, this species is listed as Data Deficient with the qualifiers of "Data Poor: Size", "Data Poor: Trend" and "One Location".