From station - Direct - take a "pilot" (2 wheeler taxi) for quick transfer, however fare would be much higher, some Rs. 100-150/-
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To reach KTC bus stand fro station, come out of the station from PF-4 side (city side). Take the straight road, walk some 200-300 mtrs, you will come to Dias Road which is one of the main roads of the city. At the very corner where the approach road meets Dias Road (Pandava Chapel junction), you would find numerous buses waiting for passengers which would take you to KTC...
more... in just Rs. 10/- per head.
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Alternatively, you may also go to municipal garden area and catch bus to Colva from there. (Buses from station to KTC have to pass by municipal garden square, so you may alight there itself and search for buses bound to Colva).