By air: Phnom Penh International Airport (PNH) sits about 10 km west of the centre. It is served by direct flights from across Southeast Asia (Bangkok, Singapore, Kuala Lumpur, Ho Chi Minh, Hanoi, Vientiane), several Chinese cities, and increasingly long-haul flights via Doha. A new airport at Techo International, 30 km south of the city, is under construction and scheduled to replace PNH later this decade. A metered taxi or Grab/PassApp ride from the current airport to the centre costs around US$12–15.
Overland from Siem Reap: the most popular long-distance route. The 320 km road journey takes 5–6 hours by Giant Ibis or Mekong Express coach (around US$15). Faster minivans do it in 4–5 hours but are less comfortable. The new Phnom Penh–Siem Reap expressway, opening in stages, will eventually cut this further.
Overland from Vietnam: regular buses run from Ho Chi Minh City (6–8 hours including the Bavet/Moc Bai border crossing). E-visas now make this straightforward — apply online a few days ahead.
By boat: tourist boats no longer run on the Mekong to Siem Reap. The fast boats from Phnom Penh to Châu Đốc (Vietnam) up the Mekong delta still operate but are slower and pricier than buses.