There are three different locations you can get on the boat: 1) The shops at Rivercenter 2) next to the Hilton palacio del Río 3) at the Aztec theatre All on the river level which you can access through the side walk. Wherever you pick up the boat is where they will drop you off.
I know of 2 for sure - 1st one is in front of the Hilton Palacio del Rio hotel, and the 2nd one is by the Thristy Aztec.
There are 2 locations one is right by the convention center
What is the cost
The easiest one is on the bottom of the Hilton, besides they have a good restaurant which you will be walking by to get to the river level.
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