Thailand operates three major mobile network operators: AIS (Advanced Info Service), True Move H, and dtac (Total Access Communication). AIS holds approximately 45 percent market share, True Move H approximately 30 percent, and dtac approximately 25 percent as of 2024. All three providers operate 4G LTE networks covering more than 95 percent of the Thai population and 5G networks in Bangkok, Chiang Mai, Phuket, Pattaya, and other major urban centers. Network frequencies include 700MHz, 900MHz, 1800MHz, 2100MHz, and 2600MHz bands for 4G, with 5G deployed on 700MHz and 2600MHz bands.
Tourist SIM cards are sold at Suvarnabhumi Airport and Don Mueang Airport in Bangkok, Chiang Mai International Airport, Phuket International Airport, and other international arrival points. AIS counters at Suvarnabhumi operate 24 hours in both Terminal 1 and Terminal 2. True Move and dtac counters typically operate from 0600 to 2200 at major airports. Prices for tourist packages start at approximately 299 baht for 15-day plans with 10-15GB data. A 30-day unlimited data plan costs approximately 599-799 baht depending on provider and speed caps. Registration requires a passport photograph and signature on a standard form; the activation process takes 2-5 minutes.
AIS offers tourist SIM packages called SIM2Fly and Traveller SIM. The 15-day Traveller SIM provides 20GB at full speed with unlimited data at throttled speeds after the cap, priced at 399 baht. True Move H sells the True Tourist SIM with 15 days and 15GB for 299 baht. dtac offers the Happy Tourist SIM with 15 days and 15GB for 299 baht and an 8-day unlimited package for 299 baht. All three operators include free domestic calls and SMS in their tourist packages. SIM cards can be purchased at 7-Eleven stores throughout Thailand, though airport counters provide English-speaking staff specifically trained for tourist activation.
Coverage in Bangkok, Chiang Mai, Phuket, Pattaya, Hua Hin, and Krabi Town maintains consistent 4G speeds of 20-50 Mbps download in most areas. Rural coverage between cities along major highways typically provides 3G at minimum with 4G available in most locations. The route from Bangkok to Chiang Mai via Highway 1 maintains 4G coverage for approximately 90 percent of the distance. Islands including Koh Samui, Koh Phangan, and Phi Phi Islands have 4G coverage in populated areas and near beaches, with signal strength diminishing in interior and mountainous sections. Similan Islands and remote sections of Khao Sok National Park have limited or no coverage.
Top-up credit can be purchased at 7-Eleven, Family Mart, Lotus's (formerly Tesco Lotus), and independent mobile phone shops displaying operator logos. Denominations start at 50 baht. AIS uses *120* followed by the voucher code and hash key for refill. True Move uses *123* followed by voucher code and hash key. dtac uses *100* followed by voucher code and hash key. Online top-up through operator mobile applications accepts Thai credit cards and international cards through some interfaces. The AIS myAIS application, True Move H TrueMove H application, and dtac dtac application allow English-language balance checking and package purchasing.
Data-only plans for tablets and secondary devices are available without additional SIM cards through data sharing features, though most tourists purchase separate SIM cards at 100-150 baht for the physical card plus chosen package. eSIM options exist for AIS and True Move H for devices supporting the technology, requiring online registration with passport upload. Physical SIM cards remain more practical for tourist use due to immediate activation and simpler troubleshooting.
Internet cafes have largely disappeared from Bangkok and major tourist areas as of 2024, replaced by universal smartphone adoption. Co-working spaces including Hubba (multiple Bangkok locations), CAMP (Sukhumvit and other Bangkok areas), and The Hive (Thonglor) offer day passes for 300-500 baht with high-speed WiFi and work facilities. Coffee shops including Café Amazon, Starbucks, Black Canyon Coffee, and True Coffee provide free WiFi with purchase, typically requiring Thai mobile number for SMS verification code. Many accept foreign numbers for this verification.
Hotel and guesthouse WiFi quality varies significantly by property age and investment level. Properties built or renovated after 2015 generally provide 10-50 Mbps speeds adequate for video calls and streaming. Older guesthouses particularly in Khao San Road area of Bangkok and budget accommodations in Chiang Mai's Old City often provide 1-5 Mbps connections shared across many rooms. The Suvarnabhumi Airport provides free unlimited WiFi throughout all terminals without registration requirements. Don Mueang Airport requires SMS verification to a mobile number for WiFi access. Shopping malls including Siam Paragon, CentralWorld, Terminal 21, and MBK Center in Bangkok offer free WiFi requiring SMS or email registration at information counters.
International roaming from Western carriers typically costs 10-15 USD per day for data packages, making local SIM purchase economically advantageous for stays exceeding two days. US carriers including Verizon, AT&T, and T-Mobile offer Thailand in their international plans, with T-Mobile including unlimited data at 2G speeds in base plans and 5GB at 4G speeds in higher-tier plans. European carriers vary by country and plan. Checking data roaming rates before arrival prevents unexpected charges, as passive roaming without purchased packages can exceed 15 USD per megabyte.
VoIP applications including WhatsApp, Line (dominant in Thailand with approximately 49 million Thai users), Facebook Messenger, and Skype function normally on Thai networks and WiFi. Line is used by most Thai businesses and individuals for communication, making it the primary application for contacting hotels, tour operators, and local services. WeChat functions but has limited Thai adoption. Telegram functions without restrictions. Voice calls over these applications provide better quality than standard international calls and no per-minute charges beyond data usage.
Portable WiFi hotspot rental services operate at Suvarnabhumi and Don Mueang airports with counters near arrival halls. Prices approximate 150-250 baht per day for unlimited data devices supporting 5-10 connected devices simultaneously. Pickup requires credit card deposit or cash deposit of 3000-5000 baht, refunded upon device return. These devices use AIS or True Move networks and provide similar coverage to standard SIM cards. They suit groups sharing one connection but cost more than individual SIM cards for solo travelers or couples with separate devices.
Bangkok provides 4G coverage throughout all districts including Sukhumvit, Silom, Siam, Chatuchak, and outer areas including Suvarnabhumi Airport surroundings. BTS Skytrain and MRT subway tunnels maintain consistent signal throughout routes. Chao Phraya River express boats lose signal in some covered pier areas but maintain connection while traveling on the river. Chiang Mai provides 4G coverage in the Old City, Nimmanhaemin Road, and tourist areas, with coverage extending to Doi Suthep mountain road and temple area. The road to Doi Inthanon has intermittent coverage with dead zones between kilometer markers 30-45.
Phuket Island maintains 4G coverage across Patong Beach, Kata Beach, Karon Beach, Phuket Town, and developed coastal areas. The interior mountain roads have coverage gaps of 5-10 kilometers in some sections. Phi Phi Islands have 4G at Tonsai Bay and Loh Dalum Bay with weaker signals at Laem Tong Beach and Long Beach. Koh Samui provides consistent coverage at Chaweng Beach, Lamai Beach, Bophut, and Nathon. Koh Phangan has full coverage at Thong Sala pier and Haad Rin (Full Moon Party beach) with limited coverage at northern beaches including Haad Yao and Haad Salad. Koh Tao maintains 4G at Mae Haad, Sairee Beach, and Chalok Baan Kao with spotty coverage at remote dive sites.
Ayutthaya Historical Park has full 4G coverage throughout the temple complex area. Sukhothai Historical Park maintains 4G coverage in the central zone containing Wat Mahathat and Wat Si Chum. Khao Yai National Park has no coverage approximately 15 kilometers inside the park from any entrance, though some high-elevation viewpoints receive weak signal. Erawan National Park maintains weak 3G coverage at the park entrance and first three waterfalls, losing signal entirely beyond the fourth tier. Khao Sok National Park has coverage at park headquarters and Cheow Lan Lake dam area, with no signal at floating raft house accommodations on the lake requiring satellite phones for emergency communication.
Network speed tests in Bangkok central districts average 40-80 Mbps download and 15-30 Mbps upload on 4G during off-peak hours of 0200-0600, dropping to 15-35 Mbps download during peak hours of 1800-2200. Chiang Mai averages 25-50 Mbps download during off-peak periods. Phuket tourist areas average 20-40 Mbps. These speeds support video streaming, video calls, and large file uploads. 5G speeds where available reach 200-400 Mbps download, though coverage remains limited to specific districts in major cities.
Thailand blocks some websites under the Computer Crime Act, particularly those deemed offensive to the monarchy or state security. Social media platforms, news sites, and communication tools function normally. Using VPN applications is common among expatriates and some tourists, though VPN use exists in a legal gray area. Pornographic content is officially blocked though enforcement is inconsistent across different sites and platforms.
Phone unlocking is required to use Thai SIM cards. Phones purchased from US carriers including AT&T, Verizon, and T-Mobile under contract periods often remain locked to the home carrier. Phones purchased unlocked or contract-free from Apple, Samsung, and other manufacturers directly typically work with Thai SIMs immediately. Testing the unlocked status before departure prevents arrival complications. Most phones sold in Europe, Australia, and Asia arrive unlocked by default.
AIS, True Move H, and dtac all operate English-language customer service lines. AIS uses 1175 with English option 9, True Move H uses 1242 with English option, and dtac uses 1678 with English option 9. Wait times average 3-8 minutes. Walking into branded stores in major shopping malls provides face-to-face English-speaking assistance in Bangkok, Chiang Mai, and Phuket. Street-level independent phone shops have limited English capability outside tourist zones.
Dual SIM phones allow simultaneous use of home country SIM and Thai SIM, enabling reception of home banking SMS codes and two-factor authentication while using Thai data. Setting the Thai SIM as default for data and the home SIM for SMS-only prevents roaming charges while maintaining verification access. iPhone models sold in the US typically lack physical dual SIM slots, using eSIM for the second line. Android models from Samsung, Xiaomi, and other manufacturers commonly include dual physical SIM trays.
SIM card registration requires passport presentation under Thai telecommunications law revised in 2021. Purchase without passport is refused at legitimate retailers. The registration links SIM card number to passport number in a national database maintained by the National Broadcasting and Telecommunications Commission. This registration theoretically expires when the tourist departs, though some tourists report SIM cards remaining functional on return visits months later if the number has not been reassigned.
Data packages can be changed mid-use through USSD codes or mobile applications. AIS users dial *777# for package menu. True Move H users dial *900# for package menu. dtac users dial *104*9# for package menu. Unused data in time-limited packages does not carry forward when purchasing a new package. Unlimited packages typically include fair usage policies reducing speeds after 1-2 GB daily usage to approximately 1 Mbps, though the throttled speed remains functional for messaging and basic browsing.
Prepaid SIM cards are the standard for tourists and short-term visitors. Monthly postpaid plans require Thai identification cards or work permits, making them inaccessible to tourists. Some expatriates on long-term visas use postpaid plans offering larger data allowances at lower monthly costs, but activation requires residential proof and Thai banking.