  We give the manifestly T-dual formulation of the massless sector of the
classical 3D Type II superstring in off-shell 3D N=2 superspace, including the
action. It has a simple relation to the known superspace of 4D N=1 supergravity
in 4D M-theory via 5D F-theory. The pre potential appears as part of the
vielbein, without derivatives.
