<p>Owing to the dispersion and multi-mode characteristics, guided wave non-destructive technology is promising for characterizing the interface state of incompressible viscoelastic multilayered soft plates. To effectively apply the guided waves in structural health monitoring, it is essential to attain a comprehensive understanding of dispersion and attenuation properties for Lamb waves in these plates, particularly those with weak interfaces. To achieve this, a hyper-viscoelastic fractional order model is employed to investigate Lamb waves in multilayered soft plates with weak interfaces. The analysis encompasses weak connections in both shear and vertical directions. An improved Legendre polynomial method with analytical integration expressions is employed to solve dynamic equations. The influence of weak interfaces, fractional order, and pre-deformation on wave characteristics is studied. Interestingly, results reveal the appearance of the transverse quasi-resonance for the S0 mode when pre-compression deformations reach sufficiently large magnitudes. Furthermore, phase velocity and attenuation variations are nonlinear as the weak interface coefficients increase. As these coefficients become adequately large, the variations diminish progressively, ultimately approaching a saturation point.</p>