[3] Tirawa was first observed by the Voyager 1 as it captured imagery of Rhea during its flyby of the Saturn system on 13 November 1980.

Though poorly imaged from the Voyager 1 encounter, Tirawa was identified as an impact structure by 1983 and provisionally named Basin A.

[1] Tirawa was later observed in greater detail by the Cassini orbiter in multiple flybys of Rhea throughout the late 2000s and the 2010s.

Tirawa is a peak-ring impact basin, with a degraded inner ring of ridges and plateaus roughly 180 kilometers across.

Tirawa is slightly elongated into an ellipsoid, with an a/b ratio of ~0.9, indicating that it was created in a low-angle oblique impact.