By Saen Saep Express Boat in Bangkok

By boat

Saen Saep Express Boat

Saen Saep Express Boat Map

The Saen Saep Express Boat serves the long Saen Saeb canal, one of the remaining canals (khlong) that used to flow through Bangkok. Mostly used by locals to commute to work, the service is cheap and you get to see the 'backside' of the neighborhoods, so to speak. Also, It is immune to Bangkok's notorious traffic jams. The total distance is 18 kilometers, and the service operates from 5:30AM till 8:30PM.
They are comparatively safe — just watch your step when boarding and disembarking as they don't stop at the pier for long and do not let the dirty water get into your eyes. To prevent splashes, the boats are equipped with little curtains that you can raise by pulling on a string, but they have to be lowered at every stop so people can clamber on board. Pay the fare (14-22 baht) to the fearless helmet-wearing ticket collectors who clamber around on the outside of the boat, ducking at bridges, as it barrels down the canal. Press the green 'bell' button if you want to get off at the next pier, else the boat might just skip it. The piers now even have (tiny) signs in English, with the exception of The Mall Bangkapi pier, and it's not obvious that you're at the mall from the canal boat!
The canal runs parallel to Phetchaburi Road, and provides the easiest access from the Golden Mount in Rattanakosin (and nearby Khao San Road) to Siam Square and Pratunam. This line is aptly called the Golden Mount Line and runs from Panfa Leelard pier to Pratunam pier in downtown. If you want to continue your journey beyond Pratunam, passengers have to change boats there. The NIDA Line starts at Pratunam and heads east to Sukhumvit and Ramkhamhaeng. Hold on to your ticket.

River taxi

Typical "long tail" river taxi

Finally, for trips outside set routes, you can hire a long-tail river taxi at any major pier. These are fairly expensive and will attempt to charge as much as 500 baht per hour, but with some haggling they may be suitable for small groups. To circumvent the mafia-like touts who attempt to get a large cut for every ride, agree for the price of the shortest possible ride (30 min), then negotiate directly with the captain when on board.

Chao Phraya Express Boat

Chao Phraya Express Boat Map

A ride on the Chao Phraya river should be high on any tourist's agenda. The cheapest and most popular option is the Chao Phraya Express Boat [12], basically an aquatic bus plying up and down the river. The basic service plies from Wat Rajsingkorn (S4) all the way north to Nonthaburi (N30), with stops at most of Rattanakosin's major attractions including the Grand Palace (at Tha Chang) and Wat Pho (at Tha Tien). The closest pier to Khao San Road is Phra Arthit. Enter the express boat at the numerous piers and pay for the trip at ticket collector, who will approach you bearing a long metal cylinder. At some bigger piers you can buy the ticket before boarding. When the metal cylinder lady approaches you, just show her the ticket you bought on the pier.
The different boat lines are indicated by the colors of the flags at the top of the boat. These flags can be confusing; don't think the yellow King's flag corresponds to the yellow line flag! There is a basic "no flag" line (9, 11 or 13 baht) that goes along all the piers, but it only runs during rush hours (Mon-Fri 06:20-08:05 and 15:00-17:30) and is fairly slow. It is better to take the faster yellow (19 or 28 baht, Mon-Fri 06:15-08:10 and 15:30-18:05) and orange (14 baht, every day 06:00-19:00) flag lines, but you have to be sure where you're going as they don't stop everywhere. The yellow line is the fastest, but is best avoided as it skips many popular attractions (including Khao San Road, the Grand Palace and Wat Pho). The orange line is your best bet, as it covers the major tourist areas and is fairly quick too.
In addition to the workaday express boat, there is also a blue flagged Tourist Boat which stops at a different subset of piers, offers commentary in English and charges a flat 150 baht for a day pass. Single ride tickets are 25 baht. The boats are slightly more comfortable and may be worth considering if you want to cruise up and down the most important tourist sights. They only operate once per 30 minutes and stop running by 3PM.
The signposting of the piers is quite clear, with numbered piers and English route maps. Sathorn (Taksin) pier has been dubbed "Central" station, as it offers an quick interchange to Saphan Taksin BTS station. The boats run every 5 to 20 minutes from sunrise to sunset (roughly from 6AM till 7PM), so ignore any river taxi touts who try to convince you otherwise.
Many piers are also served by cross-river ferries. These are particularly useful for reaching Wat Arun or the many piers at the Thonburi side of the river. Cross-river ferries run around every 10 minutes and only cost 3 baht — pay at the kiosk on the pier and then walk through the turnstile.