Thailand Rental Law 2026: Deposits, Notice, TM30

Thailand's rules for residential rentals changed in 2025, and the version still repeated on many websites — "the law applies to landlords with 5 or more units" — is out of date. This guide sets out what currently applies as of September 2026, who it applies to, and what it means in practice if you are renting long-term on Koh Samui.

Two different legal regimes, depending on your landlord

Thailand does not have one single "residential tenancy act" that covers every rental. Instead, two different frameworks apply depending on how many units your landlord rents out:

• Private landlords with 1–2 rental units fall under the general Civil and Commercial Code only. There is no statutory cap on the deposit and no statutory refund deadline — the contract terms are essentially up to what landlord and tenant agree.
• Landlords who rent out 3 or more residential units as a business are covered by a specific consumer-protection notification from the Office of the Consumer Protection Board (OCPB), which sets minimum tenant protections that cannot be contracted away.

The OCPB notification currently in force is Notification B.E. 2568, which took effect on 4 September 2025. It replaced an earlier 2018 notification that used a threshold of 5 or more units — that older "5 units" rule is now outdated and should not be relied on.

If your landlord rents out 3 or more units

Under the 2025 notification, landlords who operate as a rental business with 3 or more residential units must follow these minimum rules:

Deposit and advance rent

The security deposit and any advance rent, added together, may not exceed the equivalent of 3 months' rent. A landlord cannot ask for, say, 2 months deposit plus 2 months advance rent if that pushes the total above 3 months.

Getting the deposit back

The notification sets out clear timing for refunding the deposit at the end of the tenancy:

• If there is no damage to the property, the deposit must be refunded immediately.
• If the landlord needs to inspect the unit first, the refund is due within 7 days.
• If the landlord deducts costs for damage or unpaid charges, the remaining balance must be paid back within 14 days.

Ending the lease early

A tenant renting from one of these larger landlords can terminate the lease once at least 50% of the agreed term has passed, by giving 30 days' written notice. This gives tenants an exit option on longer contracts without being locked in for the full term.

One honest caveat: the full text of the 2025 notification has not been fully verified word-for-word in our research, and there is some uncertainty about exactly which situations count as a "rental business" (for example, units spread across different buildings). If your situation is not a straightforward single-building rental, it is worth checking directly with the OCPB hotline (1166) or a local lawyer before you sign.

If your landlord rents out only 1–2 units

Most individual condo owners, and many house and villa owners on Koh Samui, rent out just one or two properties. In that case, the OCPB notification above does not apply, and your rental sits under the general Civil and Commercial Code instead. That means:

• There is no statutory limit on how much deposit a landlord can ask for.
• There is no statutory deadline for refunding the deposit at the end of the tenancy.
• Deposit amount, refund timing, notice periods and most other terms are whatever the written contract says.

In practice, market custom on Koh Samui for these smaller private landlords is usually 2 months' deposit plus 1 month's rent in advance, but this is convention, not law — always check what your specific contract states, since it is the contract (not a general statute) that will govern your rights if something goes wrong.

Private landlord (1–2 units) vs. landlord with 3+ units

Minimum lease term and contract registration

Thai law does not set a statutory minimum length for a residential lease — a 6-month, 12-month or shorter agreement is all equally valid as a matter of contract law. What does matter is length at the other end: a lease for more than 3 years is only fully enforceable for its whole term if it is registered at the local Land Office. An unregistered long lease can still be valid as a contract, but a court will typically only enforce it for 3 years. The maximum term a lease can run, even when registered, is 30 years. For most long-term renters signing a standard 1-year (or 1-year-renewable) contract, registration is not a practical issue — it mainly matters for multi-year commercial or long personal leases.

TM30: whose responsibility is it, really?

TM30 is the notification that reports a foreign national's residence to Thai Immigration. Under the Immigration Act, section 38, the legal duty to file it sits with the landlord or house owner, not the tenant: they must notify Immigration within 24 hours of a foreign tenant moving in, and a landlord who does not can face a fine of up to 2,000 THB.

For the tenant, there is no direct legal penalty for a missing TM30 filing. The practical problem is different: immigration offices routinely ask to see the TM30 receipt for the address when you apply for a visa extension or file your 90-day report, and without it those processes can be delayed or complicated. The safest approach as a tenant is simple: when you move in, ask your landlord to show you (or give you a copy of) the TM30 confirmation for your address, and keep it with your rental documents.

What this means if you are renting on Koh Samui

In practice, most renters on Koh Samui deal with private landlords who own one or two properties — a condo, a house, or a single villa — which puts the rental under ordinary contract law rather than the OCPB notification. That is not a bad thing, but it does mean the written contract is doing all the work: read the deposit, refund and notice terms carefully before you sign, because there is no statutory backstop to fall back on if the contract is silent or one-sided. If you are dealing with an operator who manages a portfolio of three or more units, the newer 2025 protections on deposit caps, refund timing and early termination should apply — it is reasonable to ask them directly which regime they operate under.

For the practical side of finding a place and avoiding common pitfalls, see our guide on how to find a long-term rental on Koh Samui. For what rents actually look like by area and property type, see long-term rental prices on Koh Samui.

This article is general information, not legal advice — for a decision specific to your situation, confirm the current rules with the OCPB hotline (1166) or a Thailand-qualified lawyer.

Frequently asked questions

Does the new 2025 rental law apply to every landlord in Thailand?

No. It applies to landlords who rent out 3 or more residential units as a business, under OCPB Notification B.E. 2568 (in force since 4 September 2025). Private landlords with only 1–2 units are governed by the general Civil and Commercial Code instead, which does not set a statutory deposit cap or refund deadline.

Is the old rule about landlords with '5 or more units' still correct?

No, that threshold is outdated. It came from a 2018 notification that has been replaced by Notification B.E. 2568, effective 4 September 2025, which lowered the threshold to 3 or more units.

How much deposit can a landlord ask for on Koh Samui?

For landlords with 3+ units, deposit plus advance rent combined may not exceed 3 months' rent under the 2025 notification. For private landlords with 1–2 units, there is no legal cap — market practice is typically around 2 months' deposit plus 1 month advance rent, but it is set by the contract.

Who is responsible for filing TM30, the landlord or the tenant?

The landlord or house owner, under Immigration Act section 38. They must notify Immigration within 24 hours of a foreign tenant moving in. There is no direct legal penalty for the tenant if it is missed, but it can cause practical problems with visa extensions or 90-day reporting, so it is worth asking the landlord for the TM30 receipt.

Can I end my lease early if my circumstances change?

If your landlord rents out 3 or more units, the 2025 notification lets you terminate after at least 50% of the term has passed, with 30 days' written notice. If your landlord rents out only 1–2 units, early termination depends entirely on what your written contract allows.

Sources

Last checked: 19 September 2026. Facts were cross-checked against several sources; official ones take priority.

• OCPB WEB — สัญญาเช่าอาคาร เช่าอะพาร์ตเมนต์ ต้องจัดทำสัญญาเช่าอาคารตามแบบ (2026-06-08)
• OCPB sample residential lease contract (PDF) (2026-06-08)
• Notification B.E. 2568 — Royal Thai Government Gazette (2025-09-19)
• New rental contract control law in force: 3 units and up now covered (planliv.com) (2026-08-05)
• TM30 — Immigration Bureau Thailand
• Unofficial translation, Immigration Act B.E. 2522 (1979) (2025-12-26)
• Internal fact-check: rental law question, 2026-09-19-mietratgeber-welle1.md (2026-09-19)