Cantuaria lomasi is a species of trapdoor spider endemic to New Zealand.
This species was described in 1968 by Ray Forster from a single female specimen collected in Makarora. The holotype is stored at Te Papa Museum under registration number AS.000058.
The female is recorded at 15.2mm in length. The carapace and legs are orange brown. The abdomen is reddish brown.
This species is only known from Makarora in New Zealand.
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".