This selection of critical infrastructure operators in Thailand includes large established firms, predominantly in banking, telecommunications, and oil and gas. Notable companies include Siam Commercial Bank, which provides diverse financial products; True Corporation, a telecom company upgrading networks; Thai Airways International, a full-service carrier; and PTT Group, an integrated energy company. The majority of these companies are headquartered in Bangkok, indicating a concentration of essential services in the capital.
Several of these entities were founded in the mid-20th century, such as Bangkok Bank (1944) and KASIKORNBANK (1945), highlighting a long-standing presence in Thailand's economic landscape. However, there are also more recent significant entrants like ttb bank (2021). The data shows a strong presence of financial institutions, with multiple major banks listed.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
QatarEnergy LNGqatarenergylng.qa
A leading LNG producer in Qatar with a capacity of 77 MTPA, delivering clean and reliable energy worldwide while contributing to the local economy and community |
8,678 | |||
| 2 |
SCB – Siam Commercial Bankscb.co.th
Providing diverse financial products and services including retail banking, corporate finance, investment, insurance, and technological innovation for customers. |
6,786 | |||
| 3 |
True Corporationtrue.th
Telecom company upgrading networks and digital services to enhance quality of life, support innovation, and drive Thailand's digital economy. |
6,532 | |||
| 4 |
Thai Airways Internationalthaiairways.com
A full-service carrier offering passenger and cargo transportation, warehousing, ground handling, catering, and maintenance services worldwide, focusing on safety and quality |
6,283 | |||
| 5 |
Bangkok Bankbangkokbank.com
Leading commercial bank in Thailand and Southeast Asia, driving innovation in services and products to meet changing financial landscape |
5,734 | |||
| 6 | 5,348 | ||||
| 7 |
ttb bankttbbank.com
Providing comprehensive financial products and services to over 10 million customers, focusing on customer experience and sustainable growth. |
4,792 | |||
| 8 |
KASIKORNBANKkasikornbank.com
A leading Thai bank offering a wide range of financial services with a focus on customer satisfaction, risk management, and sustainable business growth |
4,381 | |||
| 9 |
Krungsrikrungsri.com
Offering diverse financial services including banking, leasing, microfinance, securities, asset management, credit cards, and venture capital investments. |
3,831 | |||
| 10 |
Krungthai Bankkrungthai.com
A financial institution focused on development, providing access to funds, financial literacy, and innovative services to strengthen the economy sustainably |
3,023 | |||
| 11 |
Thai Life Insurance Public Company Limitedthailife.com
Leading national life insurance provider offering coverage through care and compassion, operating for over eighty years as a top-ranked domestic brand. |
2,591 | |||
| 12 |
PTT Grouppttplc.com
Fully integrated energy company engaged in exploration, production, refining, petrochemical, trading, and regional energy development across ASEAN countries. |
2,476 | |||
| 13 |
BANPU Public Company Limitedbanpu.com
Global energy provider, integrating diverse energy solutions, focusing on decarbonization, gas-power-CCUS, renewables, and next-gen mining for sustainable returns. |
2,092 | |||
| 14 |
Bank of Thailandbot.or.th
Central bank maintaining economic stability, supervising banking and finance industries, protecting consumers, monitoring illegal activities, collaborating for sustainable economic development. |
1,707 | |||
| 15 | 1,640 | ||||
| 16 |
Bangkok Airwaysbangkokair.com
The company operates regional air services from Thailand to various cities in South East Asia, providing convenient travel options for passengers |
1,395 | |||
| 17 |
Allianz Ayudhyaallianz.co.th
Providing comprehensive insurance solutions in Thailand with a strong commitment to customers, employees, and partners since 1951. |
1,312 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 18 |
Muang Thai Life Assurance Public Company Limitedmuangthai.co.th
A leading life insurance company in Thailand, offering a wide range of products and services to improve customers' health and well-being |
1,254 | |||
| 19 |
Kiatnakin Phatra Financial Groupkkpfg.com
Offering banking, securities, asset management, and capital market services to support customers, employees, shareholders, and national economic growth. |
1,142 | |||
| 20 |
Thai Lion Airlionairthai.com
An airline offering superior products and services with brand new Boeing aircraft, providing the freedom to fly to destinations |
1,109 | |||
| 21 |
Krungthai-AXA Life Insurance PCL.krungthai-axa.co.th
Provides life insurance products and financial protection services through a partnership between a major bank and a global asset management group. |
988 | |||
| 22 |
Thaioil Groupthaioilgroup.com
Large integrated refining and petrochemical operation in Thailand focusing on high performance, sustainable growth, innovation, and corporate social responsibility for long-term success. |
807 | |||
| 23 |
Bangchak Corporation Public Company Limitedcareer.bangchak.co.th
Engaging in energy business, focusing on national energy security with innovation, strengthening business continuity and developing sustainability for organization and Thai society. |
757 | |||
| 24 |
PTG ENERGYptgenergy.co.th
Operate oil terminals, fuel trade, gas stations, LPG, renewable energy, logistics, equipment management, food and beverage, auto care, electronic money services. |
686 | |||
| 25 |
KTC - Krungthai Cardktc.co.th
Operates credit card business, personal loans, utility payment services, and electronic payment services under various account categories including payment service provider. |
555 | |||
| 26 |
B.Grimmbgrimmgroup.com
Operates as a multinational conglomerate across energy, healthcare, real estate, and digital technologies, with a long history in infrastructure development. |
534 | |||
| 27 |
Thai Credit Bank Public Company Limitedthaicreditbank.com
Provides comprehensive banking and financial services to customers from its headquarters in Bangkok, supporting economic growth through commercial and retail credit solutions. |
482 | |||
| 28 |
Nok Airnokair.com
A Thai airline symbolizing friendship and freedom, with a major hub in Don Mueang International Airport and serving domestic passengers in Thailand and Myanmar |
472 | |||
| 29 |
Vietjet Thailandth.vietjetair.com
Operating extensive low-cost flight network in Thailand and Vietnam, expanding across Asia Pacific, recognized for growth and employee excellence. |
368 | |||
| 30 |
Thai Smile Airwaysthaismileair.com
A subsidiary airline offering short-haul flights with a 'light premium' experience, affordable prices, and modern services on new Airbus A320-200 Aircraft |
335 | |||
| 31 | 334 | ||||
| 32 |
Gunkul Engineering Public Company Limitedgunkul.com
Manufactures electrical equipment, provides turnkey power system construction, and develops utility-scale renewable energy projects across Asia to drive sustainable and innovative energy solutions. |
313 | |||
| 33 |
Symphony Communication Public Company Limitedsymphony.net.th
Provides telecommunication services including IPLC, IP-VPN, IIG, and NIX. Delivers premium, reliable solutions, and service innovation to enhance business capabilities. |
240 | |||
| 34 |
SDEE de la Lozèresdee-lozere.fr
The company supports local authorities with rural electrification, public lighting, water, sanitation, roadworks, EV charging, renewable energy, and energy efficiency. |
10 | |||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 12, 2026.
More company lists in Thailand
- The largest companies in Thailand 158
- Multinational companies in Thailand 59
- Publicly traded companies in Thailand 48
- Retail chains in Thailand 34
- Corporate groups and holding companies in Thailand 32
- Manufacturers in Thailand 26