<p>Accurate nuclear data for neutron interactions with bismuth are crucial for applications in nuclear technology and radiation protection. This paper presents a comprehensive benchmark analysis that compares experimental data obtained at multiple angles and thicknesses with simulations based on four nuclear-data libraries: CENDL−3.2, ENDF/B-VIII.0, JENDL–5, and JEFF−3.3. The experiments involved neutron-leakage measurements of bismuth at three thicknesses and six angles, along with standard sample validations. Pulse time distributions were reconstructed using the maximum likelihood expectation–maximization algorithm, and a silicon-carbide detector was employed to accurately distinguish between deuterium–tritium and deuterium–deuterium reaction products. Simulation models validated using polyethylene sample results demonstrated calculated-to-experimental (C/E) values of 1 ± 0.03, thus confirming their reliability. The analysis revealed that CENDL−3.2 exhibited the best overall agreement in the elastic scattering region. In the discrete inelastic scattering region, JENDL–5 performed best at larger angles, while JEFF−3.3 was more accurate at smaller angles. In the continuous inelastic scattering region, JEFF−3.3 demonstrated the best overall performance, with CENDL−3.2 achieving good agreement at selected angles. In the (n,2n) reaction region, ENDF/B–VIII.0 provided C/E values closest to unity, while JENDL–5 ensured better consistency across the full energy spectrum. These findings highlight the importance of selecting appropriate nuclear-data libraries and emphasize the necessity for ongoing data refinement to improve modeling accuracy.</p>