<p>The study quantitatively investigates the cavitation flow noise characteristics of shaftless pump-jet thrusters by integrating the SST <i>k-ω</i> turbulence model, the Z-G-B cavitation model, and the acoustic finite element method. The approach systematically simulates transient flow and acoustic fields, enabling comparative analysis of cavitation noise variation under controlled flow rates and cavitation numbers. As the cavitation number decreases, the low-pressure zone on the suction surface of the axial flow pump impeller diffuses from the inlet side to the outlet side, eventually covering the entire suction surface; vapor bubbles initiate at the inlet side of the suction surface, spread toward the outlet side during development, and extend to the pressure surface under severe cavitation. Key results indicate that spectral peaks consistently appear at the shaft frequency or its first harmonic across all examined flow regimes and cavitation stages. Notably, noise amplitude and overall sound pressure level (<i>OSPL</i>) progressively increase with rising flow velocity, with severe cavitation at the rated flow rate (1.0 <i>Q</i>_<i>d</i>) causing up to a 3.1% increase in <i>OSPL</i>. Spatial distribution analysis reveals that under accelerated flow, high sound pressure level (<i>SPL</i>) zones within the impeller expand and migrate from the impeller outlet toward the blade surfaces. Additionally, shaft-frequency <i>SPL</i> exhibits a steady intensification as cavitation progresses, reaching maximum increases of 2.53% during initial cavitation and 1.96% at 1.0 <i>Q</i>_<i>d</i> flow conditions. These quantified relationships establish predictive criteria and sensitivity benchmarks, providing critical guidance for optimizing low-cavitation-noise designs in shaftless pump-jet thrusters.</p>