Sihanoukville to Prachin Buri: Road Trip Guide

Starting in 1955, Sihanoukville's deep-water port made it Cambodia's only international port, but the road east to Vietnam and then north to Prachin Buri crosses a geological boundary where the Cardamom Mountains give way to the flat alluvial plains of the Mekong Delta. The National Highway 4 (NH4) is the initial artery, and the entire journey spans roughly 600 km, typically taking 9 to 11 hours by car, depending on border crossing queues and traffic.

Along the way, you'll traverse provinces known for rubber plantations, pepper farms, and sugar palms, while the final leg into Thailand's Prachin Buri province offers a glimpse into an emerging industrial corridor. For a comprehensive method to uncover hidden gems on any route, refer to how to find the best stops and hidden gems between cities.

After leaving Sihanoukville, the first 100 km wind through the dense rainforests of the Cardamom Mountains, which catch moisture from the southwest monsoon, making this stretch particularly lush from May to October. A notable viewpoint is at Phnom Srei, where you can see the coast on a clear day.

Local commerce along the route includes roadside stands selling durian, rambutan, and other tropical fruits, especially in Kampong Speu province, famous for its palm sugar. Further east, Svay Rieng province (near Bavet) is a center for rice farming and freshwater aquaculture, with many small shops offering local grilled fish.

UNESCO World Heritage Sites are not directly on this route, but Phanom Rung Historical Park in Thailand, a Khmer temple complex, is a 2-hour drive north of Prachin Buri. For those interested in cultural history, the Killing Fields of Choeung Ek near Phnom Penh are a sobering side trip.

As you cross into Thailand, the landscape shifts to cassava and sugarcane fields, punctuated by roadside restaurants serving som tam and grilled chicken.

Driving on NH4, expect four-lane sections near Phnom Penh but two-lane rural stretches elsewhere. Cambodia's fuel price is around 4,800 riel per liter (about $1.20) as of 2025; Thailand is slightly cheaper at 35 baht per liter. Budget for tolls on Thailand's Highway 33, totaling less than $5.

• Key border crossing: Bavet/Moc Bai, open 6 a.m. to 10 p.m.
• Cambodia requires a vehicle permit if driving a foreign-plated car; purchase at the border (~$50).
• Thai insurance is mandatory; obtain at the border for about $30.
• Road quality: NH4 is paved but potholed in places; Highway 33 in Thailand is smooth.

The Araynaprathet border crossing is less busy than Bavet but closed at night. If you need a rest, the town of Neak Loeung on the Mekong River is a common stop. As you approach Prachin Buri, the industrial estates of the Eastern Economic Corridor begin, but the city itself is a base for exploring ancient Khmer temples.

NH4 has a high rate of truck accidents; stay alert and use headlights. Cambodia's traffic, like Vietnam's, is chaotic with mopeds and tuk-tuks weaving. In Thailand, traffic moves on the left; this change requires concentration after the border.

For families, there are several child-friendly attractions: the Phnom Penh Zoo (water parks) and the Forest City Complex in Bavet offer entertainment. Pet-friendly framework is limited, but some hotels in Sihanoukville and Phnom Penh accept pets; check ahead.

To manage fatigue, take a break every 2 hours. Recommended rest zones include the Ponhea Leu district food court near Phnom Penh and the GTC rest area on Highway 33 in Thailand. The route has no dedicated rest stops like at home, but convenience stores are abundant in towns.

Hidden off-route spots include the Prasat Preah Vihear ruins (though far north) and the Ta Muen Thom temple in Cambodia, but for this trip, a detour to Phnom Chisor in Takeo offers panoramic views and ancient temples, just 25 km off NH4.