Shell small for the genus, the known shell measure 4.9 mm in length. Quite globose in shape, with a small spire. The spire covers less than ¼ of the total shell length. The spire counts, after the big protoconch, 3 whorls that rapidly expand in size. The spire whorls are ribbed with shallow grooves. The body whorl is glossy but there are, seen from the ventral side, about 13 fine shallow spiral grooves. These are not obvious but discrete. The aperture is large and covers more than half of the shell length. The outer lip is thin, fragile and has a crenulate edge on the lower part. The columella is thickened, pure white in color and there is no umbilicus. The lower part of the aperture slightly turned to the left. The overall color of the shell is cream white, but on the upper part of the whorls, the zone above the two first grooves is much paler than the rest of the shell.

* Japonactaeon pusillus (E. Forbes, 1844)
This is an Atlantic species and the type species of the genus. Some specimen of J. pusillus are similar to the present species concerning shape and coloration. However, the shells of J. pusillus are usually larger, around 5 to 8 mm in length, and the body whorl is more globose in most. Some forms, as the ones figured by C.E. Rolan (2011) also have the top of the whorls in a lighter coloration.
*Japonactaeon camotensis n. sp. There is a subtle difference with this species: J. olangoensis n. sp. is more globose in shape and thinner shelled: the outline is more slender in J. camotensis n. sp.
* Japonactaeon isabella (G.T. Poppe, S.P Tagaro & Y. Goto, 2018) Will be readily distinguished by the higher spire, smaller aperture and the pastel red-brown coloration of the shells. The spiral ridges on J. Isabella are hardly visible while obvious in the present species.
* Japonactaeon valentina (G.T. Poppe, S.P. Tagaro & P. Stahlschmidt, 2015)
This species is almost double the size of the present species, is more slender and has a bigger spire. J. valentina also has a pinkish coloration not seen in J. olangoensis n.sp.

KNOWN MATERIAL AND LOCALITIES Only known from the Holotype. TYPE MATERIAL Holotype 4.9 mm. (379932). Coll. HMNS, USA.
TYPE LOCALITY
Philippines. Olango. Island. 110 m.
DISTRIBUTION AND HABITAT
Only known from the type locality.