Koh Kong has an airport but it's not currently used for commercial passenger flights. Runway is in a less than desirable shape (May '08) and airtravel will not commence commercially for a while. It is one of Cambodias greenest and most eco friendly province, with its town being very little, but surrounded by Asia's biggest tropical Mangroves, beautiful islands and mountains. Koh Kong Island is opened to the public now for day trips, and will offer the possibility to stay there starting November 2012.
Koh Kong is linked to Phnom Penh and Sihanoukville by highway 48, which branches off National Highway 4 at Sre Ambel. The road is paved and complete with 5 bridges. It's a good scenic drive through some of Cambodia's least developed and unspoiled regions - the Cardamom Mountains. Minibuses and tourist air-con buses to and from Koh Kong leave mainly in the mornings. Afternoon departures depend on demand. Tickets to Phnom Penh or Sihanoukville should cost arounf 25000 riel (US$6.25). Sihanoukville travel agencies often ask for US$8-10.
There is no longer a boat from Koh Kong to Sihanoukville. It stopped in 2009 although some travel agents in Thailand still sell travel tickets for the (non existent) boat.
There is a daily bus leaving to Koh Kong from Kep via Kampot (US$16). It leaves at 7:30 AM.
The border is at Cham Yeam, about 10 km by road northwest of the town. It faces Hat Lek in Thailand. Motos (US$2 to 2.5), shared taxis and taxis (US$9 to $10 for the entire car) run between the town and the border. Drivers will ask for more (asking for 400 baht is common) - don't let them. Negotiate in dollars rather than baht, baht prices always work out more expensive.
If you take a tuk-tuk from the border, you will have to pay 6-7 dollars for the trip, depending on