Can I use RMB directly when traveling in Sihanoukville?

Some places can't be used. It's best to exchange local money at the airport first.

This city is called Xigang for short. It is located in Sihanoukville on the southwest coast of Cambodia, named after Prince Sihanoukville. It is the largest seaport in Cambodia and the second largest city in Cambodia besides the capital Phnom Penh. At present, it is the only special economic zone in Cambodia, with a status similar to that of "Shenzhen" in China.