Hirowatari (1992) considered this species to be conspecific with Una philippensis Schröder & Treadaway, 1986 from Mindanao. The assessors follow Treadaway (1995), who regarded Una philippensis a distinct species.

Una usta is a widespread species that is usually common where it occurs. It is under no specific threat and has been assessed as Least Concern.

This species is widespread in South East Asia, from India, Burma and southern China through the Malay Peninsula, Sumatra and Borneo to central Sulawesi. 

This butterfly is a generally common, locally abundant species.

The species inhabits primary and secondary rainforest, as well as swampy areas amid forest. Adults are most frequently encountered near water courses, where males congregate in small numbers on muddy sections of creek beds, together with other polyommatine lycaenids.  

This species is not under any major threat.

No species-specific conservation measures are in place or required for this species. However, further clarification of its taxonomic status with respect to U. philippensis is needed, although this would not alter the conservation status of this butterfly.