Before you start

Your original passport — a scan or photocopy is usually refused
An unlocked phone
A sense of how often you will be in Thailand

Step-by-step

1
Buy and register at an official store
Registration against identification is legally required for all SIM purchases in Laos, and the operators require a physical passport scan at the counter. The process takes a couple of minutes. Unitel also supports registration through the LaoKYC national identity app if you would rather not queue.
In personWho: You~5–15 minSIM is inexpensive; bundles on top
2
Pick Unitel or Lao Telecom
Unitel, the Viettel joint venture, and Lao Telecom are the two most residents end up on, with the widest coverage and the best-supported apps. Smaller operators compete on price. In Vientiane all of them work; outside it, coverage is the deciding factor.
In personWho: YouMinutesFree to choose
3
Add a data bundle rather than running on credit
As everywhere in the region, raw prepaid credit is poor value. Buy a monthly data package through the operator's app or at any shop. Lao mobile data is cheap and Vientiane's 4G is perfectly adequate for video calls.
Mobile appWho: You~5 minA few dollars a month
4
Plan for Thailand
Your Lao SIM roams the moment you cross the Friendship Bridge, and residents cross frequently. Check what your operator charges, and consider keeping a cheap Thai prepaid SIM alive for hospital trips, Bangkok flights and shopping runs — many Vientiane residents do exactly this.
In personWho: YouOne extra purchaseA few dollars for a Thai SIM plus top-ups
5
Sort home internet through the building
Fibre is available across central Vientiane and is cheap. Ask the landlord what is already installed and whether the account can be transferred — new installation in an older building takes considerably longer and needs the owner's cooperation.
In personWho: You (with your landlord)Days to weeksModest monthly fee

Documents you’ll need

Original passport (mandatory; copies generally refused)
Your phone, unlocked
Vientiane address for home fibre
Cash for the SIM and bundle

Things most newcomers don’t know

Bring the physical passport, not a photo of it.

SIM registration against identification is a legal requirement in Laos, and operators require a physical passport scan at the counter — a photograph or photocopy is refused at most locations. It is a two-minute process if you have the document and a wasted trip if you do not, and it applies to eSIMs bought locally as well as physical cards.

Source: Lao operator registration requirements; LaoKYC registration process

Keep a Thai SIM alive if you cross the bridge regularly.

Vientiane residents cross into Thailand for hospitals, shopping and Bangkok flights far more often than people expect before they move. A Lao SIM roams the moment you cross, and Thai prepaid SIMs are cheap and easy to keep topped up. Having a working Thai number also means you can be reached by a Thai hospital or a Nong Khai taxi driver, which matters in exactly the situations you would rather not be improvising.

Source: community-reported

LaoKYC is the national digital identity app, and it is quietly becoming necessary.

Lao operators support SIM registration through LaoKYC, the national know-your-customer application, and its role in banking and government services has been expanding. Setting it up when you register your SIM saves you doing it later under time pressure for something more consequential.

Source: Unitel registration guidance; LaoKYC

Run two networks if you work online.

Vientiane's fixed-line and power infrastructure is less robust than a regional capital's, and wet-season faults are routine. A second SIM on a different operator with a data bundle costs a few dollars a month and turns an outage into an inconvenience. Almost everyone here who depends on connectivity for income already does this.

Source: community-reported

Common mistakes to avoid

Turning up to register a SIM with a photocopy or a photo of your passport
Crossing into Thailand on a Lao SIM and paying roaming for a routine shopping trip
Running on raw prepaid credit instead of a data bundle
Letting a number lapse and losing banking OTP delivery with it
Signing a lease without checking whether the building already has fibre

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.