Koh Rong

Hello, I am French, currently based in Vietnam for work. I need to do a business trip for few days in Phnom Phen next month (or March). I would love to use this business trip to extend few more days and visit Koh Rong.

I haven't been to Cambodia since very long time (at least 15 years ago), to Phnom Phen and Siam Reap only so I don't know much about this country.

What is the best way for short trip to reach Koh Rong from Phnom Phen? I would expect a flight to Sihanoukville? As my business trip to Phnom Phen would for 2 or 3 days, I will try to get an addionnal 3 to 4 days before returning to Vietnam.

Thanks