Visa extensions are possible inDhakaat the Immigration and Passport Office, Agargaon Rd. Fees are the same as a single-entry visa, even if just trying to expand your 15 day pittance into a full-fledged 30-90 day visa, making a sidetrip from India for longer than 15 days an expensive endeavor. If you want to stay only a little longer, it's better to just pay theoverstay feeof Tk 200/day for up to 15 days, which grows substantially to Tk 500/day thereafter. Some of the smaller backwater crossings such asTamabilmay not even notice that you've overstayed if don't point it out yourself.