Foreigners can buy land for residential purposes in Thailand.  The Department of Lands, Royal Thai Department published an article on this matter (https://bit.ly/2FU8eW0):

An alien bringing money not less than Baht forty million as specified in the Ministerial Regulation into the Kingdom for investment may apply for acquisition of land for residential purpose not more than one rai in area, provided also that permission must be obtained from the Minister.  Under section 96 bis of the Land Code, the application for such acquisition of land shall be in accordance with rules, procedures and conditions prescribed in the Ministerial Regulation as follows:

1. In the case of an alien, who brings money for investment and wishes to apply for permission to acquire land for residential purpose, shall lodge an application  (Alien 4 Form) to the competent official under section 71 of the Land Code together with the following documents:

1.1 An alien identification card issued by the Police Station in whose jurisdiction the alien is domiciled or a certificate of residence issued by the Immigration Division, National Bureau of the Royal Thai Police Force or a passport indicating the nationality of the alien;

1.2 Evidences of an investment in the business or activity that falls under Ministerial Regulation prescribing rules, procedures and conditions concerning the acquisition of Land for residential purpose by aliens B.E. 2545:

1.2.1 Letter of investment confirmation from bond seller and bonds of Thai Government, bonds of Bangkok of Thailand, bonds of State Enterprise or bonds which the Ministry of Finance secures the capital or interest;

1.2.2 Letter from the Asset Management Company confirming that an alien has invested in property mutual fund, property mutual fund or mutual fund for resolving financial institution problems established under the law on Securities and Stock Exchange, and an evidence of investment in such fund;

1.2.3 Evidences concerning investment in share capital of a juristic person who is granted promotion of investment under the law on promotion of investment, certificate of registration as a juristic person, name list of the juristic person’s share holders, and a certificate indicating that such juristic person is granted promotion of investment from the Board of Investment;

1.2.4 Evidences of engagement in an activity that entitles for being granted promotion of investment under the law on promotion of investment according to the announcement made by the Board of Investment, certificate of registration as a juristic person, name list of the juristic person’s share holders, and the Board of Investment’s letter indicating that an activity being operated entitles for being granted promotion of investment.

The evidences mentioned in para. 1.2.1 to 1.2.4 either the evidence in one para. or one combines with the other(s) can be used but the total amount shall be not less than Baht forty million.

1.3 Evidences of bringing a foreign currency into the Kingdom or the withdrawal of themoney from a foreign currency account or from a non-resident Baht account for investment.  Either one or more of the above mentioned evidences can be used but the total amount shall be not less than Baht forty million.

1.4 In the case of the land to be acquired is not located in Bangkok Metropolis, Pattaya City or Tessaban (Municipality); the letter of confirmation from the Provincial Office of Town and Country Planning is required certifying that the land to be acquired is located within a residential zone under the law on Town Planning.

1.5 Letter of Ministry of Defense or of the agency concerned confirming that such land is not located in a military safety zone under the law on Military Safety Zone.

1.6 The sketchy map showing the location of land seeking for permission.

1.7 In the case where an applicant has already had right on land by  the time the application is being lodged, an applicant shall produce such land right document;

2. A person who is granted permission shall maintain the investment period not less than five years.  He/she is required to produce the evidence of possession in the investment in 1.2 as the case may be as current, which shall be not less than Baht forty million, to the competent official according to section 71 once a year, on five consecutive years and each year shall be no later than the date making the acquisition registration of the aforementioned land.

3. A person who is granted permission shall utilized such land for a residential purpose of his/herself and the family in a way that is not contrary to the local custom or good living of the local community.

4. A person who is granted permission shall inform such land utilization for a residential purpose to the competent official of land office according to section 71 within sixty days as from the date of utilization.

5. A person who is granted permission shall facilitate the competent official supervising the use of such land to ensure that the utilization is in accordance with rules and conditions prescribed in the law once he/she receives a written notifications from the competent official under section 71.

6. If a person granted permission withdraws an investment in the business or activity before the due date of investment in 2, he/she shall inform in writing to the competent official according to section 71 within sixty days as from the date of making the withdrawal.

7. A person granted permission shall utilize such land for residential purpose within two years as from the date of the land acquisition registration.

8. If a person granted permission does not comply with the rules and conditions in 2-6, the Director General shall have the power to order such person to dispose of the land in a portion of his possession within the period of not less than one hundred eighty days and not more than one year.  If the time limit elapses the Director General shall have the power to dispose of such land.  Also, if the person does not comply with the condition in 7, the Director General shall have the power to dispose of such land.

9. Any foreign language document shall be translated into Thai language.  The translation shall be certified according to the Ministerial Regulations (B.E. 2540) issued under the Purview of Administrative Procedure Act B.E. 2539. (Phraratchabunyat Vithipratibut Ratchakarn Thangpokkhrong B.E. 2539)

10. In the case of a person bringing money into the Kingdom to the amount of Baht forty million for investment and has bought the land less than 1 rai, if later and within the period of investment, that person wishes to buy additional land, in this instance, the documents attached to the current investment can be used along with the application for acquisition of the additional land.