Upeneus mascareinsis has dorsal fins which have a total of 8 spines and 9 soft rays.

The barbels are white as is the belly while the flanks are rose-red darkening towards the back where there is some gold iridescence along the upper flanks and a dark saddle to the rear of the second dorsal fin.

The body is uniformly brown, with a little dorsal darkening, with the bars and black first dorsal-fin tip still visible in preserved fish.

[3] Upeneus mascareinsis occurs in the waters off Mozambique, Mauritius, Réunion and western Indonesia.

It was originally described in 1967 by Pierre Fourmanoir and Paul Guézé from a type found at Réunion.