Penalty clauses in Thai property contracts: how CCC Sections 379-385 work and when a court can cut them

Is a fixed penalty in a Thai villa, land or construction contract enforceable? Generally yes. Sections 379-385 of the Civil and Commercial Code (CCC) treat an agreed penalty (known in Thai as *bia prap*) as valid, and the court's main control is Section 383, which allows a disproportionately high forfeited penalty to be reduced to a reasonable amount.

The main rules at a glance

• Section 379 — trigger. If a debtor promises a sum as a penalty and does not perform properly, the penalty is forfeited once the debtor is in default.
• Section 380 — non-performance. The creditor may claim the penalty instead of performance; once the penalty is claimed, performance can no longer be demanded. If the actual loss is larger, the penalty can be claimed as a minimum and the excess proved.
• Section 381 — improper performance (for example, late). The creditor may claim both the penalty and performance, but loses the penalty if performance is accepted without reserving it. Reserve it in writing.
• Section 383 — court reduction. A disproportionately high penalty may be reduced to a reasonable amount, taking all of the creditor's legitimate interests into account, not only money. The right to ask for reduction is lost once the penalty has been paid.
• Section 384 — void obligations. A penalty attached to a void obligation is itself void.

Where penalties show up in property deals

• Sale contracts — a seller or buyer who fails to appear at the Land Office on the agreed date. See the earnest money guide and what a buyer can do if the seller refuses to transfer.
• Construction contracts — daily late-completion penalties, often expressed as a small percentage of the price per day and commonly capped around 10% (a practitioner convention, not a statutory figure). Fix the completion date and the extension mechanism in writing; see the controlled construction contract guide.
• Leases — early-termination penalties and forfeited deposits.
• Instalment sales — forfeiture of instalments paid; see hire-purchase and forfeiture risk.

Practical points for buyers and owners

• Reduction is discretionary. The court decides what is reasonable. A party who shows the other side suffered little real loss (for example, the unit was quickly resold) has a better case, but there is no guaranteed percentage.
• Raise it before you pay. Because Section 383 relief is lost after payment, a party who intends to contest the amount should not simply pay and sue later; take legal advice first.
• Penalty is not the same as earnest money. Earnest money is governed by Sections 377-378. A later payment that is really part-payment of the price is treated differently; commentary on Supreme Court decision 1511/2569 reports that a court refused to let a developer keep such a payment as security.
• Standard-form and consumer contracts are additionally subject to the Unfair Contract Terms Act B.E. 2540, which commentary describes as giving a parallel power to moderate excessive penalties and forfeited deposits.
• Agreed termination sums can be enforced in full. Commentary notes that the Supreme Court has treated a sum agreed as the price of terminating a construction contract as agreed compensation rather than a penalty.

Takeaway: a penalty clause is a real, usually enforceable cost, not a formality, and its reduction is a court remedy, not a right you can assume. Draft clear triggers, reasonable amounts and written reservations of rights, and have a Thai lawyer review any clause that fixes a large sum before you sign. The ThaiLawOnline English translations are marked as unverified against the Thai original, so rely on a lawyer for the authoritative text.