Authentic A.
Google
If you walk along the Bridge of Peace or actually anywhere in Tbilisi there a crowds of youngsters offering the boat cruise. The deal is good. 30 lari per person, includes drinks on arrival (choice of tea, coffee, juice, wine) and a 30 minute boat ride along the river. Their English is pretty good. We kept asking for a fully sheltered boat because of the heatwave and we are already quite brown in color. At the time, there weren't any available, but they arranged for a boat to swing back around and pick us up. We missed out on drinks as the cruise had already begun, but that was our choice to have full shelter at the time instead. Give it a try when you go. We went in the day whilst waiting for our hotel to check in, but think it is probably more beautiful at night.