Goniobranchus bimaensis is a species of colourful sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae.

This species is considered to be a synonym of Goniobranchus tumuliferus by Rudman.

At the very edge of the mantle is an opaque white line which is slightly variable in width.

The tips of the gill leaves and rhinophores are opaque white.

[1] Animals with similar colouration include Goniobranchus kitae which differs in having small white spots all over the rhinophores and gills and Goniobranchus tumuliferus which, as illustrated on Sea Slug Forum, is likely to include several species at present.