Seismic design of tunnels is often based on simplified models through analytical expressions for elemental geometries and structural softwares which not include soil stress path due to construction stages and the distance of the front of the excavation, resulting in overestimating the tunnels stresses. However, the development of finite differences or finite elements software has provided new tools that solve these problems and allow evaluating the seismic response through seismic records. This article compares the seismic response of NATM tunnels in soft soil of Santiago through the seismic distortion method of soil applied in a structural analysis software and a finite difference software for soil - structure interaction. Additionally, a seismic record is applied to the last case. The results of these analyses are compared in terms of seismic response of soils and structural design according to current Chilean practice.