  In this paper we present supersymmetric instanton and non-supersymmetric
wormhole solutions for the universal hypermultiplet sector of $d=4$ N=2
supergravity theories. Instantons and wormholes are constructed as saddle
points dominating transition amplitudes between states of definite axionic
shift charge, using an approach due to Coleman and Lee. Our solutions are
constructed in terms of the conserved Noether charges associated with the
global SU(2,1) symmetry of the universal hypermultiplet action. The conditions
imposed by regularity on the charges are discussed.
