There are three jetties where the sampans can pick up passengers along the Kuching Waterfront. During my visit, one of them was closed for some reason. The most popular one is the Batu Jetty near the gazebos (the waterfront's viewing decks) which is facing the Astana.
A ride in Kuching's sampan (or locally known as tambang) is probably not done by many tourists. If you think the sampans (tambangs) are just cosmetically put along the river for some added tourist traps, think again. First of all, the ride across the Sarawak River costs only RM0.30, so cheap that when I was traveling in a pax of two, I gave the boatman RM1.00 instead of waiting for my loose change. Second of all, this primordial mode of transportation is extensively used by the city dwellers to get to work in downtown Kuching Selatan. Truth be told, the closest land bridge is some kilometres away, and with the intermittent traffic jams or the public buses failing to appear on time, taking a 5-minute sampan ride into the city is not so much a bad idea after all. (Now, let's dredge a large river in downtown Kuala Lumpur and Penang, forget the expensive monorails and LRTs!).
And I must add, the so-called sunset cruises that proliferate along the Kuching Waterfront can aptly be described as tourist traps. They are nice, but expensive.
Back to the sampans. When you get into one, try your best to sit in front, right near the boatman who stands at the sampan's main deck. Clear up your mind and witness how the boatman adeptly propel the wooden boat across the river. There are two wooden oars tied in a cross-path formation which the boatman will use to navigate the sampan. If you think the boatman will row the sampan all the way, think again. There is actually a small boat engine at the back of the sampan (you can see and hear it inside the rear portion of the boat). For about a few minutes, the engine will propel the boat across the river, with the oars used to turn left or right, depending on the final destination. Interestingly, the boatman will switch off the engine at some distance away from the destination jetty and will let the boat momentum carries the sampan slowly yet steadily to the intended docking station. Very neat!
A must try. Extremely cheap. I do suggest giving the boatmen some extra tips because the official boat fare of RM0.30 is probably way too cheap. Probably a good way to make them feel appreciated for taking up a job that nobody else wants.