Phnom Penh to Sihanoukville: Road Trip Guide

National Road 4 (NR4) links Phnom Penh to Sihanoukville across 226 km of flat, then gently rolling terrain. The route begins at the capital's western edge near the Monivong Bridge (11.5519° N, 104.8736° E) and ends at Sihanoukville's port area (10.6093° N, 103.5290° E).

Originally built in the 1950s to serve the newly constructed deep-water port, NR4 passes through the provinces of Kandal, Kampong Speu, and Koh Kong. Recent upgrades have improved the road to a mostly two-lane asphalt highway, but segments remain under repair.

Just 25 km from Phnom Penh, the landscape shifts from urban sprawl to rice paddies and palm trees. Around Kampong Speu (70 km from start), you'll see the Cardamom Mountains looming to the west, a backdrop that stays with you for most of the drive.

Local commerce thrives at roadside markets, particularly around the town of Sre Ambel (116 km from start). Here, you can buy fresh coconuts and grilled meat skewers from stalls, and observe the betel nut trade that still thrives in this region.

Hidden off-route spots include the Prek Toal Bird Sanctuary, accessible via a 20-km detour near Kampong Loung (34 km from Phnom Penh). Another gem is the abandoned French-era railway bridge at Chamkar Luong (89 km), now a popular photo point.

The best stops Phnom Penh to Sihanoukville depend on your pace and interests. Most drivers complete the trip in four to five hours, but plan for longer if you want to explore.

• Fuel stations are frequent along NR4, especially near the capital and Sihanoukville; a mid-route station at Veal Renh (11.0439° N, 103.8164° E) is a reliable stop.
• Diesel averaged $1.10 per liter in 2024; a typical sedan uses about 20 liters of fuel, costing roughly $22.00.
• Tolls: There is a toll plaza near Sihanoukville (approx. $2 for cars) for the final expressway segment.

Climate and route aesthetics vary seasonally. The dry season (November–April) offers clear skies and lower humidity, while the rainy season (May–October) brings lush greenery but occasional flooding on low-lying segments.

Infrastructure safety and road quality have improved, but NR4 still has sections without shoulders and occasional potholes. Drive defensively, as overtaking is common and animals may cross.

For family and child suitability, consider scheduling a stop at the Cambodia Railway Museum in Kampong Tralach (151 km), offering hands-on exhibits and a playground. Restrooms and snack areas are available at most fuel stations.

Pet-friendly framework is limited: few official rest stops welcome pets, but the roadside picnic areas near Veal Renh are open spaces where leashed dogs can stretch. Always carry water and a leash, as shade is scarce.

Fatigue management and rest zones: plan a break every 90 minutes. The Kbal Chhay Waterfall picnic area (190 km) is an excellent midway point with shade and food stalls. If you're wondering is it worth driving Phnom Penh to Sihanoukville, the varied scenery and quick access to beaches answer with a resounding yes.