Can I buy a condo while on a tourist visa?

Yes. Your visa type has no bearing on whether you may buy a condominium in Thailand. The relevant statute is the Condominium Act B.E. 2522 (1979) as amended, which restricts foreign ownership in two ways: by quota and by the source of funds, not by visa.

The 49% rule. Section 19 bis of the Condominium Act caps total foreign ownership in any given condominium building at 49% of the saleable area. Before transfer at the Land Office (สำนักงานที่ดิน), the juristic person of the condo must issue a letter confirming the foreign quota has not been exceeded. This is the single most common reason a transfer falls through — always verify quota before paying a deposit.

The Foreign Exchange Transaction Form (FET / ธ.ต.3). The purchase price must be remitted from abroad in foreign currency and converted to Thai baht by a Thai bank in your name. The bank issues an FET form (for transfers above USD 50,000) or a credit advice (for smaller amounts) showing the funds were inward-remitted “for the purpose of purchasing a condominium.” You will not be able to register ownership without this paperwork.

Practical sequence:

1. Sign a reservation agreement and pay a small refundable deposit (typically 1–3%).
2. Conduct due diligence — title check, quota confirmation, building defects, juristic person debts.
3. Sign the Sale & Purchase Agreement and pay the contract deposit (typically 10–20%).
4. Remit the balance from abroad with the purpose clearly stated.
5. Attend the Land Office for transfer — both parties present, or via a properly notarised power of attorney.

You can do every step of this on a 30-day visa-exempt entry. What you cannot do on a tourist visa is rent the unit out commercially or manage it yourself — that requires a work permit.