eSIM for Cambodia

Cambodia is one of the easier places on this list to stay online, because two roaming partners carry the plan rather than one: Cellcard and Metfone, Viettel's Cambodian network, both running 3G and 4G/LTE. Having a second network behind you is a real advantage in a country where towers cluster around towns and highways. There is no 5G in the mix, and honestly you will not miss it; LTE handles everything a traveller here does.

Getting online when you land

Do the install at home, over wifi, and leave the line dormant until arrival. Whether you fly into Phnom Penh or Siem Reap, the arrivals process involves paperwork and queues, and fumbling with a QR code in that line helps nobody.

Once you land, switch the travel line on, allow data roaming for it, and set it as your default data connection. Keep your home SIM in the phone with data disabled so calls and one-time passcodes still reach you. The ride from Siem Reap's airport into town is a long one, and it is a good stretch to confirm your connection works before you are dependent on it.

The networks you'll be on

You will attach to whichever of Cellcard or Metfone is stronger where you stand, and in border areas or on long bus routes that failover genuinely helps. LTE is the norm in Phnom Penh, Siem Reap, Battambang and Sihanoukville. Step outside those and 3G is common, which is fine for messaging and maps and poor for anything heavy.

Cambodia is a phone-first country. Cafés, guesthouses and restaurants almost all have wifi and hand out the password without being asked, so between two mobile networks and near-universal wifi you have layers.

Where coverage holds, and where it thins

The classic route is well served. Phnom Penh holds a strong signal throughout, the Angkor Archaeological Park is covered well enough to look up which temple you are standing in, and Siem Reap's centre is dense with service. Battambang, Kampot, Kep and the Sihanoukville coast are all workable, and the National Road corridors between them keep a line most of the way.

Where it goes quiet: out on the water. The boat to Koh Rong and Koh Rong Sanloem loses signal partway, and on the islands themselves coverage is patchy and concentrated near the main beaches. The floating villages on the Tonlé Sap are unreliable once you are away from shore. The northeastern provinces of Mondulkiri and Ratanakiri have service in the provincial towns and very little in the forest and waterfall country people go there for. Preah Vihear and the remote temple sites near the Thai border are similarly thin.

What you'll actually use data for here

Ride apps do most of the work. Grab and the local tuk-tuk apps let you price a ride in advance instead of haggling in the heat, and in Phnom Penh that alone justifies the data. Telegram is unusually widely used here for business and bookings, so expect a guesthouse or a driver to ask for you on it rather than by phone.

Your Angkor pass is checked at multiple points inside the park, and having it accessible on your phone matters. Maps are worth having live rather than memorised, because Cambodian addresses often are not addresses so much as descriptions, and a dropped pin ends the confusion. Beyond that: currency conversion in your head is a nuisance without an app, bus and boat schedules shift, and translation helps once you are outside the tourist-facing places.

Before you fly

Get the eSIM installed and verified before departure, and check your phone is not carrier-locked. Download offline maps for Phnom Penh, Siem Reap and any province you are heading into, plus an offline translation pack for Khmer.

Save your Angkor pass, hotel bookings and onward bus or flight tickets as screenshots rather than links, so they open with no connection at all. If islands are on the itinerary, sort out anything internet-dependent before you board the boat; assume you are offline from the pier until you are back on the mainland. Bring a power bank and a plug adapter, and expect to charge more often than at home, since heat plus constant mapping is hard on a battery.