The Livingston to Río Dulce water taxi runs at 9:30 AM and 2:30 PM and costs Q125 ($16.65). The costs and schedule are the same whether you're leaving from the Río Dulce dock or the Livingston dock. A two way, single day ticket is also available for Q180 ($24), wherein the passenger leaves at 9:30 AM from Livingston or Río Dulce, and returns to their starting point on the 2:30 PM boat.
This route includes a tour. The boat captain visits Castillo San Felipe, the Hot Springs community project, Isla de Pajaros and a small waterfront gift shop. He also will drop passengers off at various destinations along the river. The Livingston to Río Dulce boat (as well as Río Dulce to Livingston) takes about 2 to 2.5 hours with the tour. In some cases the afternoon boat (2:30 PM) skips the tour, in which case the route takes about an hour.
The cost does not change depending on whether or not the tour is included. If you'd prefer not to have the tour, it's probably best to plan for the afternoon boat and it won't hurt to mention to the captain that you don't want a tour.
Check at the Livingston or Río Dulce public dock for most up to date information.
It's a good idea to wear a hat and sunscreen! The Livingston to Río Dulce boat is covered, but there's generally a sunny side of the boat and a few hours in sun is enough to get quite a burn.