Soil liquefaction is a geohazard that can cause severe threat to the stability of infrastructure and the phenomenon is mostly related to large earthquakes. Liquefaction analysis is a crying need for an economically fast-growing country like Bangladesh which is prone to large earthquakes because of geologic characteristics. The main focus of the study is a detailed investigation of earthquake-induced liquefaction risks along the sediment mitigation dyke (SMD) area of Matarbari deep seaport, Bangladesh—an earthquake-prone region—falls within the seismically active Zone III. Liquefaction potentiality assessment is vital to safeguard the infrastructures of Matarbari deep seaport. Four earthquake magnitudes (5.5, 6.5, 7.5, and 8.5) were selected based on historical data to assess the risk for a particular ground acceleration (amax) value of 0.28 g. Standard penetration test (SPT) values and analyzed soil engineering properties from fourteen boreholes are used to assess this area’s liquefaction vulnerability. The grain size analysis indicates the presence of sand, silt, and clay, with silty clays exhibiting low to intermediate plasticity, meeting the liquefiable soil criteria ranging from 0.05 to 2.0 mm. Liquefaction risk assessment of the SMD area was conducted with the help of analyzed values of factor of safety (FS) and liquefaction potential index (LPI) values. The observation from FS, LPI, and potential liquefaction-induced settlement patterns disclose a vulnerable zone within a depth of 0.0 to 15.0 m, characterized by FS values lower than 1.0 (FS < 1.0). However, the settlement analysis shows a limited amount of settlement throughout the depths of subsoils, approximately up to 20.0 m. LPI values were calculated for earthquake magnitudes 5.5, 6.5, 7.5, and 8.5 respectively, and based on comparative analysis, four susceptible risk zones are identified: low (0.0–5.0), medium (5.0–15.0), high (15.0–25.0), and very high (25.0–52.0). Higher risk is related to loose, uncompacted silty or sandy soils and increased earthquake magnitudes. Findings from this research can contribute to liquefaction risk management along with strategic structural planning and development in Matarbari’s SMD area. The prepared risk map will guide mitigation measures considering the major areas of potential liquefaction and help to protect the infrastructures of the deep seaport area. The findings of the study can be used as a reference for stakeholders, policymakers, and engineers involved in seismic risk assessment and infrastructure development.