Abstract: The Archimedean spiral phased array suffers from insufficient focal sound pressure. To enhance the focal sound pressure, one effective approach is to increase the transducer’s radiating area. In this paper, the Voronoi tessellation method is employed to design the element layout of the Archimedean spiral phased array, yielding two distinct tessellated array configurations. Finite element simulations are conducted to investigate the focal sound pressure, sidelobe level, grating lobe level, and beam steering range of these tessellated transducers. Results show that the packing densities of the two Voronoi-tessellated Archimedean spiral phased arrays are 81.43% and 77.94%, respectively. Compared with a conventional circular-element Archimedean spiral phased array, the focal sound pressure is improved by 51.49% and 45.28%, respectively. Moreover, introducing greater geometric randomness in the element shapes effectively suppresses the grating lobe level while preserving favorable beam steering capability. This paper also examines the influence of transducer focal length on the acoustic field of the tessellated array. Results indicate that, when the transducer’s F-number ranges from 0.85 to 0.95, it maintains higher focal sound pressure, lower grating lobe level, and superior focusing performance. The simulation results presented herein provide a valuable design reference for enhancing focal sound pressure in Archimedean spiral phased arrays.