The easiest way to reach Ko Kret is to take the once-weekly Chao Phraya Express Ko Kret tour, which leaves the Central Pier BTS Saphan Taksin every Sunday at 09:00 and visits a number of attractions before returning at 15:30. The cost of the cruise and guided tour is 300 baht no lunch. Many other companies also offer similar tours, often just as a stop on a longer upriver trip to Ayutthaya.
Independent travel to Ko Kret is a little more challenging. The easiest option is to take public bus 166 from Victory Monument at the footbridge's end or bus 505 from Central World to the end of the line in the Pak Kret market. From there, you have to walk about 500 metres or take a moto/samlor towards the river to the ferry pier, which is located behind Wat Sanam Neua.
More fun, though, is to arrive by boat. If you're willing to get up at the crack of dawn, the Chao Phraya "green flag" express boat offers a direct service from BTS Saphan Taksin to Pak Kret pier N33, but during peak hours only. As of February 2010, boats run every 15-20 min in both directions from 6:15 to 8 AM in the morning, and again from 3:30 PM to 6 PM in the evening, with no service on Sundays. The trip costs 20 baht and takes just over an hour.
Outside peak hours, the closest you can get is Nonthaburi pier, the last stop pier N30 of the normal Chao Phraya Express Boat. From here, the options are:
Take the air-con van service just 10 baht or public bus 32 to Pak Kret, then head to the ferry pier serving the island. The catch is that there's no signage in English, so finding your way can be tricky.
Hire a river taxi, for which touts will quote prices around 500 baht. With enough haggling this may be a reasonable option for a group.
If you can't get a return trip for less than 200 baht and you probably can't, it'll be cheaper to take a taxi to the temple of Wat Sanam Neua 80-90 baht in the neighbouring district of Pak Kret, from where ferries shuttle across the river to the island pretty much non-stop for the princely sum of 2 baht return. Just tell the cabbie "Ko Kret", they will understand.
Getting back is more interesting still, the easy way out again being the river taxi, plenty of which lounge about near the pier. If not, take the ferry back to Wat Sanam Neua, then take a moto or samlor out of the soi 5 baht to the main street. From here you can easily grab a taxi back to pier, or try your luck with the many buses, minibuses and songthaews heading back to central Nonthaburi and Bangkok. The pier you want to return to is Tha Nam Nonburi or simply Tha Nam Chao Phya in Thai Chao Phraya Pier.
