Bangkok was built around the Chao Phraya River and its network of canals ( khlongs) and boats are still the fastest and most comfortable way of getting around the city. The Chao Phraya Express runs large, numbered water buses between Krung Thep Bridge in the south and Nonthaburi in the north, stopping at piers ( tha) all along its course; boats (6am-7pm; every 15 min) do not necessarily stop at every landing, but will pull in if people want to get on or off. During rush hours (Mon-Fri 6-9am & 4-7pm), there are limited-stop services on set routes: a coloured flag sign on each pier shows which service stops there. The less frequent and less useful boats of Laemthong for the most part use the same piers, but don't stop at Banglamphu's Phra Athit pier.
Longtail boats ( reua hang yao) run frequently along Khlong Sen Seb canal from the Phanfa pier at the Golden Mount (handy for Banglamphu, Ratanakosin and Chinatown), and head way out east, with useful stops at Thanon Phrayathai, Pratunam, Soi Chitlom, Thanon Witthayu (Wireless), and Soi Nana Neva (Soi 3), Soi Asoke (Soi 21), Soi Thonglo (Soi 55) and Soi Ekamai (Soi 63), all off Thanon Sukhumvit. This is your quickest and most interesting way of getting across town, if you can stand the stench of the canal. Another very useful longtail service travels along Khlong Krung Kasem between Hualamphong Station and Banglamphu, depositing passengers near the New World department store before terminating at a tiny pier off Thanon Phra Athit (every 20-30min; 15min; B6). It's also possible to get a longtail from Hualamphong to Phanfa pier.