The current work uses validated finite element models to evaluate the performance of high pressure-high temperature (HP/HT) offshore pipelines to combined seismic and operational loads. Safety of the pipeline is investigated under different load-paths and with different pipe-soil interaction models. In a parametric study, structural responses of the pipeline SDR (diameter to wall-thickness ratio) at different in-service temperatures are assessed. Results are compared to codified recommendations. It is shown that in offshore pipelines with larger SDR, typically used in shallow waters, the combined loading imposes a higher risk.