Using mobile data in Cambodia: what to expect
Cambodia surprises a lot of first-time visitors with how usable its mobile data is. Operators like Smart, Cellcard and Metfone have built out 4G that covers the cities and the main tourist routes well, and prepaid data here is among the cheapest in Southeast Asia. That said, buying a local SIM means a passport-registration step at a phone shop — a recent regulatory requirement that's now enforced — and quality between carriers varies street to street, with Smart generally regarded as the most consistent for travellers. A travel eSIM gives you a clean alternative: it connects automatically when you arrive, latches onto a strong local network, and skips the registration counter entirely. That matters more than it sounds when you land late at Phnom Penh after a long-haul flight and just want to head straight to your guesthouse without negotiating a SIM purchase.
Coverage across Cambodia
Phnom Penh has the best and most consistent service, with fast 4G across the riverside, the Central and Russian markets and the BKK1 district where most visitors stay. Siem Reap — your base for Angkor — is well covered in town and holds a usable signal around the headline temples like Angkor Wat and the Bayon, though it can fade among the more remote ruins out toward Banteay Srei and Beng Mealea. The coastal towns of Sihanoukville and the more laid-back Kampot and Kep are fine for everyday use. Where coverage genuinely drops is on the islands such as Koh Rong and Koh Rong Samloem (patchy and slow once you're off the main beach), in the forested northeast highlands around Mondulkiri and Ratanakiri, and along some of the rougher rural roads between provinces. The sensible move is to download Google Maps offline for any region before you head into the hills or out to an island.
How much data you'll need
Day-to-day in Cambodia you'll lean on Google Maps for navigation, the local PassApp plus Grab for tuk-tuks and cars (Grab is the dominant ride-hailing app here), Google Translate's camera for Khmer menus and market signs, and a mix of Telegram and WhatsApp for messaging — Telegram is especially widely used locally, so expect guesthouses and tour operators to message you there. Most travel here is light on data and heavy on photos at the temples and along the Mekong. A rough guide: a few days around Phnom Penh and Angkor runs about 3-5 GB; a one-to-two-week loop adding the southern coast lands near 8-15 GB; and if you stream on the long, slow bus and boat rides between towns, size up accordingly. The plans above lay out the current options so you don't have to guess.
Keep your number and WhatsApp
Run the travel eSIM next to your usual SIM in dual-SIM mode. The eSIM handles all your data, while your home number stays live for calls, texts and the two-factor codes your bank sends, and WhatsApp keeps running on your normal number with no re-verification. Just remember to turn your home SIM's data roaming off in settings — that single switch is what stops it quietly charging you international rates in the background while the eSIM carries the load. Keep the home SIM active for calls and SMS only, and let the eSIM do everything data-related.
Before you fly
Check that your phone supports eSIM before anything else — most iPhones since the XR, along with recent Samsung Galaxy, Google Pixel and a few Honor models, are good to go; our compatibility checker confirms it instantly. Set the eSIM up on home Wi-Fi before you leave, while you have a stable connection and time to spare, and it'll activate when you touch down at Phnom Penh (PNH) or Siem Reap (the new Siem Reap-Angkor airport, SAI). You'll have data ready for that first tuk-tuk negotiation before you've even cleared the terminal, which also makes it easy to pull up your booking confirmation or a map pin for the driver.
Hopping through Southeast Asia?
If Cambodia is part of a longer overland trip, an Asia regional plan keeps one eSIM connected as you cross into Vietnam, Thailand or Laos — no shop-hopping or new passport registration for a SIM at every border.