You just signed a lease on a condo near Thong Lo BTS, your Wi-Fi gets installed next Thursday, and your home country SIM card is bleeding roaming charges every time you open Google Maps. Sound familiar? Getting a local phone plan is one of the first things you should do after landing in Bangkok, right up there with finding an apartment and learning which 7-Eleven has the best coffee. Thailand has three major carriers, and choosing between them can feel confusing. Let me break it all down so you can stop overpaying and start streaming.

The Big Three: AIS, True, and DTAC at a Glance

Thailand's mobile market is dominated by three players. AIS is the largest network with the widest coverage across the country. True is deeply integrated into the True ecosystem, which includes True WiFi hotspots, TrueVisions cable, and TrueMove H mobile. DTAC, now merged with True under a parent company, still operates as its own brand with separate plans and pricing. For most expats living in central Bangkok, all three will give you solid 4G and 5G coverage.

Here is where it gets interesting though. If you live in a high rise near Asok BTS or Phrom Phong BTS, signal strength in your condo can vary by carrier. I once had a friend in a unit on the 34th floor of Ashton Asoke paying for an AIS plan but barely getting two bars indoors. He switched to True and the problem disappeared. The building's internal signal boosters were tuned to True's frequency. So before you commit to a 12 month postpaid contract, buy a cheap prepaid SIM from each carrier and test them inside your actual condo.

Prepaid vs Postpaid: What Actually Makes Sense for Expats

If you are staying less than six months, prepaid is the obvious choice. You can grab a tourist SIM at any airport kiosk or any 7-Eleven for around 299 to 599 THB, loaded with data that lasts 7 to 30 days. AIS and True both sell them at Suvarnabhumi arrivals. Top ups are easy through the carrier apps or at convenience stores all over the city.

For expats on a one year lease, postpaid plans offer much better value. AIS postpaid packages start around 599 THB per month for 20 to 30 GB of data, unlimited calls, and 5G access in supported areas. True has competitive plans at similar price points, often bundling perks like free TrueID streaming. DTAC's postpaid options tend to be slightly cheaper, with packages around 499 THB per month, though data caps can be tighter.

The catch with postpaid is paperwork. You will need your passport, a valid Thai work permit or a long term visa, and sometimes a credit card. If you are on a tourist visa, some branches will still set you up, but expect to pay a deposit of 2,000 to 3,000 THB. The flagship AIS store at CentralWorld near Chit Lom BTS is probably the smoothest experience for English speaking sign ups. True's main store at Siam Paragon is equally expat friendly.

Data, Speed, and Coverage: Real World Differences

In most of inner Bangkok, from Saphan Khwai down to Bearing BTS, all three carriers deliver solid 4G speeds. You will stream Netflix in your condo near On Nut BTS just fine on any of them. The real differences show up when you leave the city. AIS consistently wins for upcountry coverage. If you plan weekend trips to Kanchanaburi or Chiang Rai, AIS will keep you connected on mountain roads where True and DTAC sometimes drop out.

For 5G specifically, True has rolled out the most aggressive coverage in central Bangkok. Walk around Siam Square or Sukhumvit Soi 11 and you will likely pick up True 5G signals. AIS is close behind, with strong 5G nodes around Silom, Sathorn, and the Rama 9 business district. DTAC's 5G rollout has been slower, though the True merger should change that over the next year or two.

One practical example. A couple I know renting a two bedroom unit at Life Ladprao, right next to MRT Phahon Yothin, runs a small online business from home. They tested all three carriers and found AIS gave them the most consistent upload speeds for video calls, averaging around 30 to 40 Mbps up. True was close at 25 to 35 Mbps. They pay 799 THB per month on an AIS postpaid plan with 50 GB and have never had a dropped Zoom call.

eSIM Options and Digital Nomad Friendly Features

If your phone supports eSIM, both AIS and True let you activate plans digitally without visiting a store. This is a game changer if you arrive late at night or just hate waiting in line. The AIS app walks you through eSIM activation in about ten minutes. True's process is similar through the True iService app. DTAC also supports eSIM but the activation process can be glitchy for non-Thai phones.

For digital nomads bouncing between a coworking space on Ekkamai Soi 2 and a cafe near Ari BTS, having a reliable local number also matters for registering with Thai apps. Food delivery, ride hailing, and banking apps all require a Thai mobile number for OTP verification. This alone makes a local SIM essential, not optional.

My Recommendation for Most Expats

If you want the safest all around choice, go AIS. Best nationwide coverage, solid speeds in Bangkok, easy English language support, and straightforward postpaid plans. If you already use True internet in your condo, bundling with a True mobile plan can save you 10 to 15 percent monthly. DTAC is fine on a budget, but with the ongoing merger into True, its standalone future is uncertain.

Whatever you pick, get it sorted in your first week. A working Thai phone number makes everything easier, from setting up utility accounts to ordering midnight pad kra pao from GrabFood. And if you are still searching for the right condo before you even think about phone plans, check out superagent.co. The AI powered platform matches you with verified Bangkok rentals fast, so you can get settled and get connected without the usual headaches.