Electroelastic waves in piezoelectric media are widely used in sensing and filtering applications. Despite extensive research, computing the guided wave dispersion remains challenging. This paper presents semi-analytical approaches based on spectral methods to efficiently and reliably compute dispersion curves. We systematically assess the impact of electrical boundary conditions on a 128 ° Y-cut LiNbO 3 wafer, examining open–open, open–shorted, and shorted–shorted surface configurations. Multi-modal dispersion maps obtained from laser-ultrasonic experiments for each boundary condition exhibit excellent agreement with the computational predictions. A straightforward implementation of the spectral collocation method is made available as GEW piezo plate ( https://doi.org/10.5281/zenodo.14205789 ), while the spectral element method is integrated to GEWtool ( http://doi.org/10.5281/zenodo.10114243 ) for multilayered plates. Therewith, we aim to make advanced semi-analytical techniques more accessible to physicists and engineers relying on dispersion analysis.