Hi Sushmit, I had travelled to Andaman from Kochi, Kerala. Our itinerary is shared below. Day 1
Flight from Kochi to Chennai, then Chennai to Port blair
Took a taxi from Airport to Cellular Jail. Watched the light and sound show. Stayed at Port blair Day 2
City shopping
Visit to museum
Off to harbour. Took Makruzz ship from the boat jetty. Reached Havelock island.
Stayed at hotel Kingdom. Day 3
Sunrise at Kalapathar beach
Water sports, scuba diving, sea walking and snorkeling Elephant beach
Radhanagar beach Day 4
Return to port blair from Havelock via Makruzz
Return flight
Cheap way is take a train reach chennai
1.train cochin - chennai ( 350 approx)
then
2.ship chennai - port balir ( 750 approx )
3.port blair to havelock ship