Geophysical investigation is non-invasive, time and cost effective. There is a relation between geophysics and geotechnical data. Unfortunately many engineers did not aware of this or have lost confidence in geophysics, as a result of insufficient communication of the capabilities, limitations and precision of the geophysical approach; poorly planned investigations; or lack of data integration. With good communications and planning, geophysics can be used together with borehole, excavation data or others to provide greater certainty of site characteristics. Three geophysical investigations case studies were discussed with different objective for assessment and design. The case studies illustrated how geophysical data can provide important geological interpretation that could not be achieved by interpretation from borehole results alone.