Ferry services on the Chao Phraya river start at Central Peir with the Chao Phraya Express Boat Service. All day regular ferry tickets are 150 Baht (price may have increased) and can be very crowded at peak times due to people going to work or on their way home, but it's very cheap and great fun. It is not recommend taking young children at peak times as this would be risky. Purchase the Chao Phraya Tourist Boat travel guide when you pay for your ticket as this shows all the piers along the river with the main tourist destinations to visit. It would take two or three days to see most of the attactions.
Private tours on long boats cost a great deal more but is much more relaxing with just two or a few people. Private tours can take you up the many khlongs (canals) that diverge of from the main river. You can also book large tourist boat rides during the day and dinner cruises at night. Be wary of strangers acting as touts approaching you at the piers offering private boat tours at exorbitant prices.
Click on the gallery photos below.