Locally resonant acoustic metamaterials enable strong manipulation of sound waves using subwavelength inclusions. In this work, we consider a particularly simple and well-known resonator that couples efficiently with acoustic waves: the gas bubble. When embedded in a soft host medium, gas bubbles exhibit strong resonance, induce dispersion and nonlinear behavior, making them attractive building blocks for acoustic metamaterials. We develop a two-dimensional numerical model to study nonlinear sound propagation in bubbly media, focusing on the acoustic response of non-homogeneous bubble distributions. The model couples the acoustic wave equation with a modified Rayleigh–Plesset equation formulated in terms of bubble volume variation and incorporates a linear Kelvin–Voigt viscoelastic model for the host medium. The governing equations are solved using finite-difference schemes in time and finite-volume techniques in space. Numerical simulations demonstrate that a single layer of bubbles immersed in a soft viscoelastic medium can act as a highly efficient acoustic absorber and shield. These effects arise from the strong coupling between the incoming acoustic wave and the local resonances of the bubbles. The influence of bubble size, density, spatial arrangement, and host-medium elasticity on resonance and absorption mechanisms is analyzed. The proposed framework provides a simple and efficient route for the design of multiphase, locally resonant acoustic metamaterials. Future work will extend this approach to finite element simulations and experimental investigations, paving the way toward tunable and robust acoustic metamaterial designs.