Closed-form solutions are presented for an unsupported shallow circular opening subjected to Rayleigh waves. It is assumed that the ground is homogeneous and elastic, that the wave motion is perpendicular to the tunnel axis, with motions on the plane of the cross section of the tunnel. Thus, plane strain conditions apply. A quasi-static analysis is taken because Rayleigh waves have a large wavelength, arguably of the order of kilometers and velocities about 10% smaller than that of shear waves. Complex variable theory and conformal mapping are used to reach the solution, which is given as a system of equations that provides the parameters of the complex analytic functions needed to compute stresses and displacements. Solutions are found for drained and undrained loading conditions. For the latter, the principle of effective stresses is assumed, which requires no volume change of the ground during the passage of the Rayleigh wave. Because the vertical and horizontal free-field motions of the Rayleigh waves are out of phase, the stresses and displacements induced are also out of phase and cannot be superimposed. Thus, stresses and displacements obtained from the free-field motions are also out of phase, uncoupled and treated separately. The results show that the normal stress terms induced by the free-field motions dominate the response of shallow tunnels and that stresses and tunnel distortions decrease with tunnel depth. An additional solution for a deep circular tunnel subjected to Rayleigh waves is also proposed. A comparison between stresses and displacements obtained with the assumption of shallow or deep tunnel suggests that the largest demand on the tunnel can be approximated with the solution for a deep tunnel, for tunnels at depths larger than about five to six times their radius.