The　seismic　performance　of　monopiled　offshore　wind　turbine　(OWT)　structures　was　evaluated　numerically.　The　aim　was　to　analyze　offshore　wind　farm　sites　on　complicated　layered　seabed　with　high　seismicity.　Following　pile　soil　analysis　(PISA)　model,　three-dimensional　(3D)　numerical　evaluations　were　undertaken　for　two　separate　locations　under　two　independent　seismic　events.　The　effects　of　pile　diameter,　depth,　site　impact　owing　to　transverse　soil　layering,　uni-directional　and　multi-directional　seismic　loading　and　seismic　acceleration　magnitude　are　presented.　Dynamic　impedance　depth　variation　and　site　response　analysis　via　lateral　displacement,　lateral　soil　response　and　Fourier　response　amplitude　are　explored　in　frequency　and　time　domain.　In　a　seismic　zone　with　stratified　soil,　pile　diameter　has　a　greater　influence.　Variations　in　soil　profile　affect　wind　turbine　performance　and　seismic　sensitivity.　This　research　will　give　a　strong　platform　for　later　studies　to　recommend　a　safe　wind　farm　site　based　on　simulation　results.