  We develop an embedding formalism for $(p,q)$ anti-de Sitter (AdS)
superspaces in three dimensions by using a modified version of their
supertwistor description given in the literature. A coset construction for
these superspaces is worked out. We put forward a program of constructing a
supersymmetric analogue of the Ba\~nados metric, which is expected to be a
deformation of the $(p,q)$ AdS superspace geometry by a two-dimensional
conformal $(p,q)$ supercurrent multiplet.
