The Ultimate Due Diligence Checklist for Buying Property in Koh Samui

August 31, 2025

Your Safeguard in Paradise – Why Due Diligence is Non-Negotiable

The dream of owning a villa with a private pool and a spectacular sea view in Koh Samui is easy to fall in love with. The island's beauty, welcoming culture, and lucrative market for Koh Samui Villas for Sale are a powerful combination. However, behind every beautiful property lies a complex legal and administrative framework, especially for foreign buyers. This is where the concept of "due diligence" becomes your most critical tool.

Due diligence is a comprehensive investigation of a property before you sign the final purchase agreement. It’s the essential process of verifying legal ownership, checking for encumbrances, and confirming that the property you are about to buy is exactly what it is represented to be. In the Thai real estate context, where legal systems and land titles can differ significantly from Western norms, due diligence is not a mere formality—it is a non-negotiable step that protects your investment and provides peace of mind.

This guide is your definitive due diligence checklist for buying property in Koh Samui. It's designed to demystify the process, breaking down the complex legal and administrative steps into an easy-to-follow, actionable plan. We’ll cover everything from verifying the authenticity of the title deed to investigating the seller's background and ensuring all taxes have been paid. This is the ultimate resource to help you navigate the process confidently, with the knowledge of a local expert.
 

Part 1: Legal Due Diligence – The Foundation of Your Purchase

The legal integrity of a property is the cornerstone of a secure investment. This phase of due diligence is the most critical and should always be performed by a reputable, independent Thai lawyer specializing in property law.

Step 1: Land Title Verification & Search

The land title deed is the single most important document you will encounter. It is the definitive proof of ownership and the most secure form of land title in Thailand is the Chanote.

• Actionable Items:
  • Verify the Seller's Ownership: The lawyer will perform a search at the local Land Department to confirm that the seller is the registered legal owner of the property. This is a crucial step, especially in cases where the property is being sold by a company or an agent acting on a Power of Attorney.
  • Check for Encumbrances: The back of the title deed reveals the history of the property. Your lawyer must meticulously check for any existing mortgages, liens, easements, or other legal charges. A mortgage registered against the property, for example, must be settled by the seller on or before the day of transfer.
  • Confirm Title Authenticity: Your legal representative will confirm that the title deed is genuine. Unfortunately, forged or fraudulent deeds do exist. A physical check at the Land Department is the only way to be 100% certain.
  • Validate Land Boundaries: The Chanote title deed includes a cadastral survey with GPS coordinates, ensuring the land boundaries are accurate. However, for older deeds or in areas where this is not standard, it’s vital to ensure the physical boundaries of the property match the official documents.
     

Step 2: Understanding & Verifying Property Ownership Structure

For foreign buyers, understanding the different ownership structures is essential. Thai law prohibits foreign nationals from owning land outright in their name (with very limited exceptions).

• Actionable Items:
  • Condominium Freehold: If you are buying a condo, you must verify that the building's foreign ownership quota (49% of the total sellable area) has not been exceeded. Your lawyer will obtain this information from the Land Department.
  • Leasehold Agreement: For houses and villas, a long-term leasehold is the most common and secure ownership structure for foreigners. The due diligence must include a thorough review of the lease agreement. The lawyer will check for key clauses, including:
    • The lease term (usually 30 years, with options for renewal).
    • The validity of the renewal clauses and whether they are legally enforceable.
    • The right to sublease, mortgage, or sell the property.
    • Clear and fair terms for rent payments, maintenance, and insurance.
  • Company Ownership: If the property is owned by a Thai Limited Company, extensive due diligence is required. This is a complex area and requires specialized legal expertise.
  • Verify Company Registration: Your lawyer will verify the company's registration documents, corporate affidavit, and shareholder list to confirm the company's legitimacy and ownership structure.
  • Check for Debts and Liabilities: A thorough check of the company's financial records is necessary to ensure there are no hidden debts or ongoing lawsuits that could impact the property's value or your investment.
  • Review Articles of Association: The company's articles must be reviewed to ensure they are structured correctly for property ownership and your rights as a director or shareholder are fully protected.
     

Step 3: Permits and Compliance Check

Just because a property is built doesn't mean it was built legally. Verifying all necessary permits is crucial to avoid future legal headaches, fines, or even demolition orders.

• Actionable Items:
  • Building Permits: Your lawyer will visit the local municipal office (Or Bor Tor) to check that all buildings on the property, including the main house, swimming pools, and any guesthouses, have a valid building permit.
  • Compliance with Regulations: Permits must be compared to the actual structures to ensure the building adheres to the approved plans, height regulations, and any specific land allocation laws. Cases of illegal construction are a real risk.
  • Environmental Impact Assessment (EIA): For larger developments or properties in sensitive areas, an EIA report is required. Your lawyer will verify that this has been completed and approved by the relevant authorities.

Part 2: Financial & Administrative Due Diligence – Securing Your Investment

Financial and administrative checks are vital to ensure the transaction is clean and you don’t inherit any unexpected financial liabilities.
 

Step 4: Financial Verification and Tax History

• Actionable Items:
  • Check for Outstanding Taxes: Your lawyer will check with the local tax office to ensure all past property taxes and land taxes have been paid by the seller. Any outstanding tax bills will become your responsibility after the purchase.
  • Utility Bill Verification: Check for any outstanding electricity, water, or internet bills. While these are typically minor, it's good practice to ensure a clean slate upon transfer.
  • Common Area Fees: If the property is part of a managed estate or development, your lawyer will confirm that all common area fees have been paid up to date and check the financial health of the juristic person (the management company). This ensures the estate is well-maintained and free from debt.

Step 5: Seller & Developer Background Check

The integrity of the seller or developer is just as important as the property's legal status. A background check can uncover potential red flags.

• Actionable Items:
  • Developer Reputation: For off-plan or new developments, you must research the developer's track record. Has the company completed projects on time and to the promised quality? Your real estate agent or lawyer should provide references and show you past projects.
  • Check for Lawsuits: Your lawyer can perform a check with the local court to see if the seller or developer has any ongoing or past legal disputes related to property or finance.
  • Review Past Transactions: You can check the history of the property's title to see how frequently it has been bought and sold, which can sometimes indicate a problem.

Part 3: Physical & Practical Due Diligence – The On-Site Inspection

After all the paperwork has been reviewed, a thorough physical inspection of the property and its surroundings is the next crucial step.
 

Step 6: On-Site Physical Inspection

• Actionable Items:
  • Structural Integrity: For existing buildings, a professional building survey should be conducted. This will identify any structural issues, such as cracks in the foundation, water damage, or electrical problems.
  • Boundary Confirmation: Verify that the physical boundaries of the land match the dimensions and markers in the title deed. This is especially important for land plots and older properties.
  • Access & Road Right of Way: Confirm that the property has legal and unhindered access to a public road. Lack of proper road access can significantly devalue a property and lead to future disputes.
  • Utilities & Services: Verify that the property is connected to essential utilities like electricity and water. Check the quality and reliability of the connections. Is there a reliable water source (e.g., government water, well water, or a shared system)?
  • Surrounding Environment: Assess the area. Are there any nearby developments, industrial zones, or environmental hazards (e.g., flood zones, unstable slopes) that could impact the property's value or your quality of life? This includes checking local development plans at the municipal office.
     

Step 7: Rental & Market Due Diligence

If you plan to use the property as an investment, this step is essential to confirm its financial viability.

• Actionable Items:
  • Rental Yield Analysis: Research the average rental yields for similar Koh Samui villas for sale in the same area. A reputable real estate agent can provide you with data on occupancy rates and nightly rental prices.
  • Competitor Analysis: Evaluate the property's competition. What are the unique selling points (e.g., location, view, size, amenities) that will make it stand out in the rental market?
  • Long-Term Market Trends: Assess the broader Koh Samui market trends. Is the area experiencing growth, or is it stagnating? What does the future look like for tourism and infrastructure development?
     

Your Partner in a Secure Investment

Navigating the real estate market in Koh Samui can be a life-changing experience, but it requires diligence and expertise. The process of due diligence is your shield against potential risks and a guarantee that your investment is sound. While this checklist provides a comprehensive overview, it is by no means a substitute for professional, independent legal counsel.

At Conrad Properties, we don't just find you a property; we guide you through every step of this critical process. Our team of experienced real estate professionals works hand-in-hand with trusted Thai lawyers to ensure that every property we present has been meticulously vetted. We believe in complete transparency and empower our clients with the knowledge they need to make the best decisions.

From the first viewing of a breathtaking Koh Samui villa to the final signing of the transfer papers at the Land Department, we are your trusted partner. By following this due diligence checklist, you are not just buying a property—you are securing your future in paradise.

If you are ready to begin your search or have found a property you are interested in, contact us today. Let's start the due diligence process and turn your dream of owning a piece of Koh Samui real estate into a secure, joyous reality.