Seismic anisotropy parameters (φ, δt) were estimated between 2016 and 2021 using records from the Colombian National Seismological Network (CNSN) stations and related to regional tectonic features in NW South America. To achieve it, we studied the polarization of S-wave phases of local events (associated with Nazca-South America and Caribbean-South America subduction processes) and SKS phases of teleseismic events. The local events used in this study are deeper than 70 km and Mw≥4.5. The teleseismic events have epicentral distances between 90°-130° and Mw≥6.5. We found seismic anisotropy linked to structural control in the crust, suggesting a dominant S-wave polarization inside the faults rather than polarization due to the regional tectonic field stress. Erratic patterns of φ due to the possible presence of fluids in the crust were interpreted, and orientations of asthenospheric flow under the subducting slabs were inferred with a generalized convergence-oriented SW-NE under NW South America.