Best eSIM for Thailand 2026: Complete Network, Coverage & Island Guide

Why You’ll Want an eSIM for Thailand in 2026

More than 35 million international travelers flocked to Thailand in 2025 — making it the most-visited country in Southeast Asia. Whether you’re hopping on the BTS Skytrain in Bangkok, booking a Grab from Chiang Mai’s Night Bazaar, or sharing selfies from the Full Moon Party on Koh Phangan, you need reliable mobile data as soon as you step off the plane.

Here’s something most travel guides won’t tell you: Thailand’s telecom landscape changed drastically in 2023 when DTAC merged with TrueMove H to form True Corporation. The country now has just two major networks — and which network your eSIM connects through affects your coverage everywhere, from Bangkok’s underground MRT to Pai’s mountain valleys.

In this guide, we’ll cover the networks, destination-by-destination coverage across Thailand’s islands and cities, why Grab and LINE won’t work without data, how to stay connected while island hopping, and the cheapest way to get reliable internet for your whole trip.

Thailand’s Mobile Networks: What Changed and Why It Matters

Thailand once had three major mobile networks. In March 2023, DTAC merged with TrueMove H to create True Corporation. This changed the landscape significantly, and it matters for which eSIM to buy.

AIS (Advanced Info Service) — Best Overall Coverage

AIS is Thailand’s biggest carrier with 46% market share and the largest geographical coverage in the country. It has the most 5G towers and the most rural coverage. AIS delivers Thailand’s strongest signal on islands, in mountains, and in remote areas. If your eSIM routes through AIS, you’ve got Thailand’s best network for a tourist who leaves Bangkok.

True Corporation (True + DTAC Merger) — Strong in Cities

True has about 33% of the market following the merger with DTAC and TrueMove H. The combined network is competitive in Bangkok and other major cities, with strong 5G coverage across urban areas. It does lack some coverage on islands and remote provinces while the two legacy networks integrate. If you’re visiting cities, True is a solid option. If you want to go island hopping or into the mountains, AIS is the stronger pick.

NT (National Telecom) — Irrelevant for Tourists

A small government-owned operator with no presence in the international eSIM world. Not relevant to travelers.

5G in Thailand

Thailand has made strong progress with 5G. AIS and True Corporation have launched networks across Bangkok, Chiang Mai, Phuket, Pattaya, and other major tourist areas. Real-world speeds sit in the 150-400 Mbps range in 5G zones, with 30-80 Mbps on 4G/LTE. For tourists, 4G is more than enough speed for navigation, messaging, streaming, and video calls — 5G is icing on the cake when available.

eSIM Coverage in Thailand by Destination

Thailand’s coverage varies wildly between the underground transit system in Bangkok and beaches on remote islands. Here’s what to expect at each major destination.

Bangkok

Coverage: Excellent on both networks. Thailand’s capital has near-100% 4G/LTE coverage and growing 5G from AIS and True Corp. BTS Skytrain, MRT subway, shopping malls, Khao San Road, Sukhumvit, Chinatown, and the Grand Palace area all have strong signal. MRT underground stations have coverage on both networks — you can use Grab, Google Maps, and messaging apps while riding the subway. Suvarnabhumi and Don Mueang airports both have excellent coverage to activate your eSIM the minute you deplane.

Chiang Mai

Coverage: Excellent in city, variable in mountains. The Old City, Night Bazaar, Nimmanhaemin Road, and all the popular digital nomad coworking spaces are well covered by both networks. Chiang Mai’s famous temples — Doi Suthep, Wat Chedi Luang, Wat Phra Singh — are also well covered. AIS is noticeably stronger in the surrounding countryside — Mae Sa Valley waterfalls, Doi Inthanon National Park, and the hill tribe villages north of the city. If you’re renting a scooter and exploring into the sticks, the better coverage from AIS-routed eSIMs becomes apparent.

Phuket

Coverage: Good to excellent. Patong Beach, Phuket Town, Kata, Karon, and the airport area all have strong coverage from both networks. The western beaches are also well covered. Some of the interior jungle areas and less-developed beaches on the east coast have weaker True Corp signal. AIS is more consistent across the whole island. The Big Buddha viewpoint and boat tours of Phang Nga Bay maintain signal on AIS.

Koh Samui

Coverage: Good on main roads, patchy in interior. Chaweng Beach, Lamai Beach, Bophut, Nathon, and the airport all have strong coverage. The inside of the island — especially around jungle waterfalls and viewpoints — is patchier, with AIS edging out True Corp in those areas. You’ll maintain signal around the ring road, but cut inland and True Corp tends to drop out.

Koh Phangan — Full Moon Party Network Coverage

Coverage: Variable — and it matters most during Full Moon Party. Thong Sala (the main town), the Full Moon Party beach at Haad Rin, and Srithanu all receive coverage from both networks. However, when 10,000-30,000 people crowd onto Haad Rin beach during Full Moon Party, network congestion is severe. AIS performs slightly better than True Corp thanks to more tower capacity on the island.

Tip: Whatever you want to upload, do it before midnight or wait for the morning. On either network, trying to post or stream between 11pm and 3am is near-impossible. Download any maps you need beforehand, and take a screenshot of your Grab booking for when you leave the party.

Koh Lipe, Koh Lanta, and the Andaman Islands

Coverage: Basic to limited. Koh Lanta has decent coverage on the main parts of the island via AIS, but weaker True Corp signal. Koh Lipe is only covered near Walking Street and the main beaches — head to the quieter parts of the island and signal can drop entirely. On boat trips between islands, expect no signal. AIS is the only viable network on many of the smaller Andaman islands. If you’re island hopping in this region, your eSIM needs to use AIS.

Krabi and Railay Beach

Coverage: Good in Ao Nang, weaker at Railay. Both networks have decent coverage in Krabi Town and Ao Nang. Railay Beach — only reachable by boat — has weaker coverage, particularly at the eastern beach and the lagoon area. The Phi Phi Islands are covered in Tonsai Bay, but signal is limited throughout the rest of the islands.

Pai

Coverage: Unreliable outside town centre. Pai’s small centre has generally good coverage, but this is where plenty of travelers get into trouble — the canyon viewpoints, Pai hot springs, waterfalls, and mountain roads outside town all have massive dead zones, even on AIS. True Corp is noticeably worse outside the centre. If you’re driving the famous 762 curves from Chiang Mai to Pai, don’t expect signal for much of the way through the mountains. Download offline maps before heading to Pai.

Pattaya

Coverage: Excellent. Walking Street, Beach Road, the entertainment district, and all resort areas — both networks have seamless 4G/5G. Pattaya’s proximity to Bangkok means well-maintained infrastructure. No problems for tourists here.

Khao Sok, Khao Lak, and National Parks

Coverage: Limited in the parks, good in the towns. The towns around national parks have coverage, but inside Khao Sok National Park, at Cheow Lan Lake, and deep in the jungle, say goodbye to signal. AIS has slightly better coverage at the park peripheries. Overnight lake house stays at Cheow Lan? No mobile data — a digital detox you didn’t sign up for.

Grab, LINE, and Thai Apps: Why Your eSIM Is Essential

This is the part of the guide that most competitor guides conveniently skip over. If you’re traveling to Thailand, this section is critical.

Grab — Your Transport Lifeline

Grab is your primary option for getting around in Thailand. And it requires a data connection at all times. Bangkok’s taxi network has a bad reputation — drivers refusing to turn on the meter, taking roundabout routes, or flat-out refusing your destination. Grab eliminates all of that with fixed pricing and GPS tracking.

You need data to:

• Book your ride (no offline mode available)
• Track your driver and confirm they’re on their way
• Navigate to the pickup point
• Pay via the app (cash payment also available)
• Order via GrabFood

Important: Your Grab account is verified via SMS using your phone number. Set up and verify Grab at home using your regular SIM before traveling. Once verified, the app works on any data connection — including your eSIM. No Thai phone number needed afterwards.

LINE — Thailand’s WhatsApp

LINE is the dominant messaging app in Thailand — with over 54 million users. If you want to communicate with your hotel, tour operators, or even book restaurants and transport, you’ll need LINE. Some Thai businesses don’t use email or standard SMS — just LINE.

Download and install LINE before heading to Thailand and add your hotel and tour operators’ LINE IDs. Messages, voice calls, and video calls through LINE all work via your eSIM data connection — no Thai phone number required.

Other Apps That Need Your Data

• Bolt — Alternative to Grab in Bangkok and Chiang Mai. Worth having as a backup.
• Google Maps — Essential for real-time navigation. Thai road names are complex, and you can’t rely on downloaded maps for tuk-tuk or songthaew routes.
• Google Translate — Reading Thai script on signs, menus, and tickets without a translation app is a pain. The camera function is a lifesaver.
• Foodpanda / LINE MAN — Popular food delivery apps in Thai cities. Both need data.
• Klook / GetYourGuide — Many Thai attractions use digital tickets. You’ll need data to display them at the gate.

Staying Connected Between Islands: Thailand’s Island-Hopping Reality

Connectivity between islands is a challenge that no other guide covers properly.

Signal Coverage in Open Water

You’ll lose signal on ferry rides between islands — Koh Samui to Koh Phangan, Krabi to Koh Lanta, Phuket to Phi Phi — because even AIS can’t maintain a consistent signal in open water. Signal returns when approaching the destination island.

Coverage Rankings for Island Hopping

• Strongest coverage: Koh Samui, Phuket, Koh Chang — good signal from both networks in major beach towns.
• Good coverage: Koh Phangan, Koh Lanta, Koh Tao — AIS solid, True Corp adequate in main areas.
• Basic coverage: Koh Lipe, Koh Mak, Koh Kood — AIS covers main towns, dead spots common.
• Poor coverage: Similan Islands, Surin Islands, remote Andaman islands — expect no reliable signal.

Practical Tips for Island Hoppers

• Download offline maps for each island before leaving the mainland.
• Take screenshots of ferry timetables and hotel reservations — don’t rely on loading them at the pier.
• Save your hotel’s LINE ID and phone number before you depart.
• Book speedboat and ferry tickets through your hotel rather than trying to buy online at the pier.
• If you’re doing a multi-island trip, an AIS-routed eSIM is essential — True Corp has too many gaps in island coverage.

Thailand’s Digital Nomad Visa and eSIM for Remote Workers

Thailand’s Long-Term Resident (LTR) visa and Destination Thailand Visa (DTV) are attracting a growing community of digital nomads and remote workers. If you work remotely from Thailand, your eSIM needs will be significantly different from a 2-week tourist.

Data Requirements for Remote Work

• Video calls (Zoom, Google Meet, Teams): 1-2 GB/hour. A full work day with 3-4 hours of calls = 3-8 GB/day.
• General remote work (Slack, email, cloud apps): 500 MB-1 GB/day.
• Total monthly data: 30-60 GB is reasonable for a full-time remote worker.

Top Destinations for Digital Nomads

Chiang Mai is still #1 — affordable coworking spaces (Punspace, CAMP, Yellow), fast café WiFi, and excellent mobile coverage across the entire city. Bangkok has a world-class coworking scene (The Hive, Hubba, WeWork) and superb 5G coverage. Koh Phangan has a growing digital nomad community but mobile coverage is patchy — rely on coworking space WiFi for video calls and your eSIM for everything else.

eSIM vs Local SIM for Long Stays

For trips under 30 days, an international eSIM like eSimy is the easiest option — no registration hassle and no need for a Thai phone number. For stays longer than 2 months, some digital nomads pair an international eSIM for data with a cheap local SIM for a Thai number (useful for banking apps and local services). However, Thailand requires biometric verification (passport scan and selfie) for local SIM purchases — which is exactly why international eSIMs are so much easier.

How to Choose the Best eSIM Plan for Thailand

Choose a data plan based on how long you’ll be traveling:

Short City Breaks (1-5 Days)

Bangkok weekend or Chiang Mai short break? With hotel WiFi handling most of the heavy lifting, 1-3 GB will suffice. Grab rides, mapping, messaging, and social media throughout the day are well covered by this amount.

Standard Holidays (7-14 Days)

The classic Bangkok–Chiang Mai–Koh Samui/Koh Phangan route? 5-10 GB is the sweet spot. Daily mapping, booking Grabs, social media updates, Google Translate, and moderate video calls home should all be covered.

Island-Hopping Adventures (14-21 Days)

Longer trips across multiple islands with limited WiFi? 10-15 GB gives you comfortable daily use. Islands generally have fewer WiFi options than cities, so you’ll lean on mobile data more for navigation and communication.

Extended Stays (30+ Days)

Working from Thailand? Depending on your video call schedule, you may need 20-50 GB. Use coworking WiFi for heavy tasks and combine with your eSIM for everything else. Check out eSimy’s Thailand options for the best deal on larger data bundles.

A Note on “Unlimited” Plans

Thai “unlimited” eSIM plans typically throttle speeds once you hit the daily Fair Usage Policy cap (500 MB-1.5 GB per day). Once throttled, speeds drop to 128-256 kbps — enough for messaging but nowhere near enough for booking Grabs, mapping, or uploading photos. A plan with a set data allowance at full speed is often the better choice.

SIM Registration in Thailand — What Tourists Need to Know

In Thailand, all SIM cards — including tourist SIMs — require mandatory registration. If you buy a SIM at the airport or at a 7-Eleven, you’ll need to show your passport and have your photo taken. This is required by the NBTC (National Broadcasting and Telecommunications Commission).

Because your eSIM is provided by an international carrier — not a Thai carrier — you don’t need to register. No passport, no photo, no waiting in the airport SIM counter queue. One of the biggest practical advantages of buying your eSIM before you arrive is skipping this entire process.

How to Install and Activate Your Thailand eSIM

Step 1: Buy Before You Arrive

Browse eSimy’s Thailand eSIM plans and choose a data bundle that fits your itinerary. Purchase from home — your eSIM profile will be ready before arrival.

Step 2: Install the eSIM Profile

Once purchased, scan the QR code to download the eSIM profile onto your phone. Installing the profile saves it to your device — it will NOT activate your plan or start consuming data.

On iPhone: Settings → Cellular → Add eSIM → Scan QR Code

On Android: Settings → Network & Internet → SIMs → Add eSIM → Scan QR Code

Step 3: Activate Upon Arrival

When you land at Suvarnabhumi or Don Mueang, go to Settings and enable the eSIM data line. Your data plan begins at this moment — you’ll have connectivity before clearing customs.

Step 4: Configure Dual-SIM

Keep your home SIM active for calls and SMS verification. Set the eSIM as your data line. WhatsApp, LINE, and other messaging apps will continue working on your home number while you browse on Thai mobile data.

Step 5: Book a Grab

With data live, open Grab and book your ride from the airport. The fixed-price, air-conditioned ride eliminates any haggling with taxi drivers. Worth it especially since the Suvarnabhumi taxi queue can stretch to 30-45 minutes during peak arrival times.

Free WiFi in Thailand: A Backup, Not a Solution

Thailand has plenty of free WiFi spots, but they come with real limitations.

Where You’ll Find Free WiFi

• Cafés — Almost all cafés offer WiFi, though speeds vary.
• Shopping malls — Most large malls have free WiFi.
• Hotels and hostels — Nearly all provide WiFi, but speeds can be painfully slow at peak times.
• 7-Eleven stores — Many branches have free WiFi.
• Airports — Free WiFi in all major airport terminals.

Why WiFi Isn’t Enough

• Speeds are inconsistent — Public WiFi quality varies wildly depending on how many people are connected.
• No coverage between stops — You can’t navigate or use Grab while walking between WiFi hotspots.
• No Grab without cellular — Grab can be unreliable on public WiFi, especially for real-time driver tracking.
• Islands have limited WiFi — Outside main towns, free WiFi options disappear quickly.

Use free WiFi for heavy downloads and video calls. Use your eSIM for everything that matters on the move — Grab, navigation, LINE, and translation.

Thailand Travel Tips

• Install Grab before you arrive. Download and verify your account at home so you can book rides immediately on landing.
• Carry cash. While Thailand is becoming more cashless, many vendors, street food stalls, and restaurants still only accept cash.
• Withdraw larger amounts less often. Thai ATMs charge a fee on every international withdrawal. Take out more each time to minimize fees.
• Download offline maps. Coverage is spotty in some areas. Having offline maps for your destinations will save you when signal drops out.
• Use Google Translate’s camera. Thai script is beautiful but unreadable for most visitors. Point your camera at signs and menus for instant translation.
• Book overnight trains and buses early. Popular routes sell out quickly, especially during holidays and high season.

Frequently Asked Questions

Do I need to register my eSIM in Thailand?

No. While local SIM cards purchased in Thailand require passport verification and a photo, international eSIMs are exempt from this requirement. You simply buy, install, and activate.

Which network is best for tourists in Thailand?

AIS (Advanced Info Service) offers the best overall coverage for tourists, especially those traveling beyond Bangkok to islands and national parks. AIS has the largest market share (approximately 46%) and its signal strength is superior in remote areas compared to True Corporation.

Will my eSIM work on Koh Phangan during Full Moon Party?

Your eSIM will work on Koh Phangan, but data speeds will be severely reduced when 10,000-30,000 people crowd Haad Rin Beach during the Full Moon Party. Upload photos and content before or after the event for best results.

Can I use WhatsApp with my eSIM in Thailand?

Yes. Set your eSIM as the data line and keep your home SIM for calls and SMS. WhatsApp and all other messaging apps will continue working on your original number using the eSIM’s data connection.

Will Grab work with my eSIM?

Yes. Grab relies on data to operate, so it works perfectly with your eSIM. Make sure you set up and verify your Grab account at home before traveling. Once your eSIM is activated in Thailand, you can hail rides and order food immediately.

Is there mobile coverage in Pai?

Pai town centre has adequate coverage, but surrounding attractions have poor and unreliable signal. Dead zones are frequent on the canyon viewpoints, hot springs, and waterfalls. The 762-curve mountain road from Chiang Mai has intermittent signal loss. Download offline maps before visiting Pai.

How much data do I need for a week in Thailand?

For a typical tourist using Grab, maps, LINE messaging, social media, and Google Translate, 5-7 GB per week is sufficient. Lighter users who rely on hotel WiFi for photo uploads can get by on 3-5 GB. Heavy users streaming or posting videos should budget 10+ GB per week.

Does eSIM work on Thai islands?

Major islands like Koh Samui, Phuket, and Koh Phangan have good coverage in tourist areas. Smaller islands such as Koh Lipe, Koh Mak, and Koh Kood have basic coverage with common dead zones. Remote islands like the Similans and Surins have little to no coverage.

Is 5G available for tourists in Thailand?

Yes. AIS and True Corporation both offer 5G in major tourist cities including Bangkok, Chiang Mai, Phuket, and Pattaya. Real-world 5G speeds are typically 150-400 Mbps, though 4G/LTE speeds of 30-80 Mbps are already more than sufficient for all tourist activities.

Has DTAC been discontinued?

DTAC merged with TrueMove H to form True Corporation in 2023. The DTAC brand is being phased out. Existing DTAC eSIMs will connect through the True Corporation network. Coverage remains similar, but True Corporation is consolidating all services under its own brand.