Chiang Khong is the Thai counterpart to the Lao border town of Huay Xai, just across the Mekong. Chiang Khong is a small, sleepy town with one main road and no night life. It has a Friday market, a lot of temples, a craft village with a busy market and a temple. The best time to visit is from October to January, or on the April 18 Giant Catfish Festival when baby giant catfish are taken to the Mekong river.
From Huay Xai in Laos by a short ferry trip (10,000 Kip) across the Mekong (6am to 6pm). Thai Immigration here seems to lack both computers and the annoying cameras now installed in Bangkok's airport and, consequently, is extremely quick. However, arriving by this overland route means that you will only be given a visa-exempt entry valid for 15 days, compared with the 30 days you would get flying into Bangkok. The ferry is at the northern end of Chiang Khong: if you want to move on without stopping in the city, take a tuktuk to the bus station in town for 30 baht per person, or you can walk 3km.
From Chiang Rai local buses go regularly (mostly every half hour) from 5.00 AM to 16.00 PM. It should take about 2h but the driver may take it slow and could stop for dinner, so probably 2.30h or more. From Chiang Mai by minibus for 250 baht or by "green bus" (making many stops) for about 200 baht, by public bus is 150-270 bath. anyway the most advised way is to go by bus to Chiang Rai for 94-263 baht (3h) and then take a bus to Chiang Khong.
By bus from other major cities in Northern Thailand and Isaan. Daytime and overnight buses run directly from Bangkok's Northern Bus Terminal (Moh Chit) to Chiang Khong every day. There are also 5 overnight buses from Moh Chit which leave at 19.00 pm and arrive at Chiang Khong the next morning at 8.00 am, and one daytime bus which leaves Moh Chit at 7.00 am and arrives in Chiang Khong at 20.00 pm.
The riverfront area can be seen on foot but it's worth getting a tuk-tuk or taxi for the trip out to the bus station. Small ferries cross the river every few minutes for about 40 baht (10,000 kip). The border crossing closes at 18:00.
If you want to look around Chiang Khong the best way is rent a bike or motorbike to visit local villages and the banks of the Mekong.
There are several ATMs in the town - Kasikorn Bank, GSB, Siam Commercial Bank, Krung Thai Bank and a new machine in front of the 7/11 at the bus station. All banks are closed on Saturday and Sunday but you should be able to use the ATMs. If you are heading to Laos get your money here because in houay xai the maximum withdrawal per transaction is 700,000kip and exchange rates from baht to kip are quite ok.
Laos currency (kip) can only be officially exchanged inside Laos. Thai banks will not exchange Laos currency. Chiang Khong ATM will not disburse kip. Chiang Khong moneychangers will exchange for a fee. The Laos bank in Huay Xai and the ATM there will disburse kip. Thai baht and US dollars are readily accepted in Laos. At good rates.
Laos visas are more economical if bought with US dollars instead of baht.
There are very few bars as such in Chiang Khong. Your best bet for evening entertainment is a Big Chang beer/Singha Beer at your guesthouse.
There have been reports from travellers that there are wild/feral dogs which come out in this town late at night.
It seems very popular for guides on the pre booked slow boat trip to try encourage people to switch to the bus to Luang Prabang for the same price. They tell horror stories of floods, mosquito hordes, unexpected third nights spent on the slow boat and crooks in Pak Beng. Presumably this is designed so they can pocket the difference between the cheaper bus ticket and the slow boat you already paid for when you pre booked. On our trip (July 2011) around 80% of the group decided to take the bus instead. Many other groups on the slow boat commented that this was also the case in their groups. Don't Fall for it!!
Getting to the slow boat requires an exit stamp from Thailand Immigration(about 5 minutes), crossing the river (about 5 minutes), getting a Laos visa (about 20 minutes), and go upriver about 1km. Walk or tuk-tuk.
Prices for the two day slow boat to Luang Prabang vary. As of April 2012 tickets bought in Chiang Khong cost 1180 baht. However as soon as you clear immigration in Huay Xai they can be bought for 950 baht and allegedly even cheaper from the boat pier itself. Thai baht, US dollar and Lao Kip are all accepted at least as far as Luang Prabang.