Foreign investment in telecommunication business, with the exception of Type 1 licensed business (which include internet access service, audiotext service, resale of public switched telecommunications service; store-and-retrieve value-added service; international calling card service) is limited to 49% of equity ownership. For the pruposes of the OECD FDI Regulatory restrictiveness Index, it is assumed that all mobile telecommunication services, except those related to type 1 licensed business, are subject to the foreign shareholding limitation.
"Section 4
In this Act, “foreigner” means:
1. a natural person who is not of Thai nationality;
2. a juristic person not registered in Thailand;
3. a juristic person registered in Thailand, being of the following descriptions: 
a. being a juristic person at least one half of capital shares of which are held by persons under (1) or (2) or a juristic person in which investment has been placed by the persons under (1) or (2) in the amount at least equivalent to one half of the total capital thereof;
b. being a limited partnership or a registered ordinary partnership the managing partner or the manager of which is the person under (1);
4. a juristic person registered in Thailand at least one half of the capital shares of which are held by persons under (1), (2) or (3) or a juristic person in which investment has been placed by the persons under (1), (2) or (3) in the amount at least equivalent to one half of the total capital thereof; [...]"((Foreign Business Act, B.E. 2542 (1999))
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"[...] CHAPTER I - TELECOMMUNICATIONS BUSINESS LICENSING
Section 7.  Any person who wishes to operate a telecommunications business in accordance with the characteristics and categories prescribed in the Notification by the Commission under the law on the organisation to assign frequency spectrum and to regulate radio broadcasting, television and telecommunications businesses shall obtain a license from the Commission.
There shall be three types of a telecommunications business license as follows:
(1)    Type One License: being a license for the telecommunications business operator who does not have his or her own telecommunications network and the characteristics of his or her business are deemed appropriate to provide services on the basis of liberalisation. When the person wishing to operate the business with such characteristics has notified the Commission, the Commission shall issue a license for business operation;
(2)    Type Two License: being a license for the telecommunications business operator who has or does not have his or her own network and whose business is intended to provide services for a limited group of people or has no significant impacts on free and fair competition or on public interest and consumers. When the person wishing to operate the business with such characteristics has completely fulfilled the standard criteria prescribed in the Notification in advance by the Commission, the Commission shall issue a license for business operation;  
(3)    Type Three License: being a license for the telecommunications business operator who has his or her own network and whose business is intended to provide services to a large number of the general public or may have significant impacts on free and fair competition or on public interest or requires special consumer protection. When the person wishing to operate the business with such characteristics has been considered appropriate by the Commission for the issuance of a license, such person may then commence the operation.
The characteristics or categories including the scope of services of telecommunications business to which the licensee under Type One, Type Two or Type Three is entitled shall be as prescribed in the Notification by the Commission, which shall be in accordance with the characteristics of business operation of each type of license under paragraph two and shall take into account the development of diverse service provisions of telecommunications business and fairness among operators.
In applying for a license, the applicant shall specify the type of the license to be applied for together with the characteristics or categories of telecommunications business he or she wishes to operate. If he or she wishes to engage in any additional business operation of different characteristics or categories after he or she has been licensed, he or she shall inform the Commission prior to the commencement of such operation. In this case, the Commission may prescribe conditions to be observed by the applicant.
Section 8.  The Commission shall prescribe in the Notification and disclose to the general public the licensing criteria to enable the person who wishes to operate the business to be informed in advance of the applicant qualification, the application procedure and the license granting criteria. The granting criteria shall be determined differently in accordance with the types of license under section 7 and shall be consistent with each characteristic and category of telecommunications business and the guidelines on frequency spectrum licensing and telecommunications business licensing as stipulated in the Telecommunications Master Plan and the Frequency Plan under the law on the organisation to assign frequency spectrum and to regulate radio broadcasting, television and telecommunications businesses.
In the Notification under paragraph one, the Commission shall prescribe details in relation to the applicant qualification, the application procedure, the documents, evidence or information necessary for the licensing procedure, the licensing consideration procedure, the consideration period of the Commission, scope of license, maximum and minimum term of license including other conditions necessary for business operation.
Determination of the applicant qualification shall be in accordance with the following criteria:
(1)     the applicant for Type Two License and Type Three License shall not be a foreigner under the law on foreign business. In this regard, the Commission may require the applicant for certain characteristics or categories of telecommunications business who is a juristic person to prescribe the prohibition of any act which has the nature of business takeover by a foreigner [as amended by the Telecommunications Business Act (No. 2), B.E. 2549 (2006).];
(2)     the applicant shall not be bankrupt;
(3)     the applicant shall not have previously had a telecommunications business license revoked;
(4)     the directors, managers or persons having management power of the applicant shall not have been sentenced by a final judgment for an offence under this Act or under the law on telegraph and telephone, the law on radio communication or the law on consumer protection during a two-year period prior to the filing of the application for a license;
(5)    the applicant for Type Three License shall have an investment plan and a service provision plan for telecommunications business that enables the efficient service provisions;
(6)    the applicant shall have other qualifications and have no other prohibited characteristics prescribed by the Commission for each type of license under section 7. [...]" (TELECOMMUNICATIONS BUSINESS ACT, B.E. 2544 (2001))
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"[...] Appendix C - Examples of Telecommunications Business Services Requiring Type One Licence
Examples of Telecommunications Business Services Requiring Type One Licence:
1) Internet Access Service; 2) Audiotext Service; 3) Resale of Public Switched Telecommunications Service; 4) Store-and-Retrieve Value-Added Service; 5) Public Chain Payphone Service; 6) International Calling Card Service
Appendix D - Examples of Licence-Free Telecommunication Business Services
Examples of Licence-Free Telecommunications business Services:
1) Mobile desk telephones (desk cellular phones); 2) Coin-slot pay telephones stationed at homes and shops"(Notification of the National Telecommunications Commission - Re: Nature and Categories of Telecommunication Business Requiring Telecommunications Business Licence)
Foreign Business Act, B.E. 2542 (1999)
TELECOMMUNICATIONS BUSINESS ACT, B.E. 2544 (2001))
TELECOMMUNICATIONS BUSINESS ACT (No. 2), B.E. 2549 (2006).
Notification of the National Telecommunications Commission - Re: Nature and Categories of Telecommunication Business Requiring Telecommunications Business Licence
[<a href="https://investmentpolicy.unctad.org/investment-laws/laws/40/thailand-foreign-business-act">Act</a>],[<a href="http://www.krisdika.go.th/wps/portal/general_en/!ut/p/c5/04_SB8K8xLLM9MSSzPy8xBz9CP0os3g_A2czQ0cTQ89ApyAnA0__EIOAQGdXAwNDc6B8JG55dzMCuv088nNT9SP1o8wRqowczd0MHC29vAO8PUMM3Z3N9CNzUtMTkyv1C3IjyvMdFRUByl01jw!!/dl3/d3/L0lJSklna2shL0lCakFBRXlBQkVSQ0lBISEvWUZOQzFOS18yN3chLzdfTjBDNjFBNDFJMkE3RjBBOUpLUEtJVDFHQzY!/?PC_7_N0C61A41I2A7F0A9JKPKIT1GC6_WCM_CONTEXT=/wps/wcm/connect/ksdkwebcontent_en/legal+translation/legal+english/telecommunications+business+act+be+2544+%282001%29#_ftnref3">Act</a>],[<a href="http://thailaws.com/law/t_laws/tlaw0461.pdf">Act</a>],[<a href="http://lib.nbtc.go.th:8080/aion-streaming/access.do?p=Y29udGVudCUyRmVib29rJTJGMjAxNTA3MDJfMTQzNTgwMzM1MTU4OF8xOTc3LnBkZg==&m=stream">Notification</a>]