Why would you want to get a sea plane endorsement? There is only 1 sea plane operator in India. Have you checked with them?
To get a sea plane endorsed on your Indian license, you require 10hrs on type along with 5 take off's and landings as PIC. If you're looking to get a C208 endorsed on your license, you would require to do around 5hrs basic float rating on a 180/206. Then advance yourself on to the 208. The whole program would cost you around 28000 USD. Are you willing to spend that much for a single engine turbo prop job?
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