For import and export enterprises in Thailand, these financial documents constitute your “lifeline”:

As a founder with long-standing engagement in Thailand, I possess a deep understanding of the complexity of import and export operations. In Thailand, financial documents related to import and export activities are far more than routine accounting records; they represent a critical lifeline that determines whether an enterprise can clear customs smoothly, manage legal risks lawfully, and even ensure its survival. Many enterprises do not intentionally violate regulations; however, due to fragmented documentation chains or data inconsistencies, they are frequently labeled as “high risk” under scrutiny by tax authorities or customs.

Today, drawing upon TMA GROUP’s extensive practical experience serving hundreds of enterprises in Thailand, I will systematically outline the core financial documents in import and export operations that are both mandatory and must be accurate, thereby assisting you in building a robust and resilient compliance framework.

I. The “Legal Closed Loop” of Import and Export Operations: Four Core Statutory Documents

Conclusion: These four documents constitute the cornerstone of the legal closed loop governing import and export transactions. The absence of any single document or any inconsistency in data may call the compliance of the entire transaction chain into question and subsequently trigger in-depth reviews by tax authorities or customs.

1. Commercial Invoice

Core assessment: The commercial invoice is the “core document” of import and export transactions; it serves not only as the basis for accounting recognition but also as the principal evidence used by customs and tax authorities to assess transaction authenticity and value.

Price anchor: It provides the direct basis for customs price declarations and for the calculation of customs duties and import VAT.

Financial foundation: It is used by the finance function to recognize revenue or procurement costs, thereby influencing corporate profitability and tax exposure.

Completeness of information: It must include buyer and seller details, product descriptions consistent with the HS Code, quantities, unit prices, total values, currency, and applicable trade terms (such as FOB, CIF, and EXW).

Data consistency: The most critical risk lies in ensuring that invoice amounts are fully consistent with customs declaration values and contractual pricing. Any discrepancy may be regarded as an “abnormality” and serve as a trigger for tax audits.

What I often state directly to clients is: “Your commercial invoice embodies both the pricing authority and the compliance identity of your import and export operations.”

2. Packing List

Core assessment: The packing list serves as a “manual” of the physical condition of goods; although it does not directly involve monetary values, it is an important supporting document for customs inspections, inventory management, and cost accounting.

Customs inspection: It is a primary reference used by customs officers to verify whether the goods are consistent with the declaration.

Inventory management: It is a key document for warehouse receipt, issuance, and stocktaking, ensuring consistency between records and physical inventory.

Quantity verification: It is used to reconcile actual delivered quantities with those stated on the commercial invoice.

Indirect evidence: During tax or customs spot checks, the packing list effectively substantiates the physical existence and commercial reasonableness of the transaction.

3. Bill of Lading / Air Waybill

Core assessment: The bill of lading or airway bill constitutes legal evidence of cargo ownership and transportation traceability and serves as the sole legitimate basis for recognizing international logistics costs in accounting.

Proof of title: It evidences ownership of the goods and the contractual relationship governing transportation.

Cost recognition: It is the lawful supporting document for booking international freight, insurance, and related logistics costs.

Transportation traceability: It records key information such as the origin, destination, and carrier, thereby forming a complete logistics chain.

Risk alert: In the absence of this document, even where freight invoices exist, tax authorities may deem the evidence insufficient, thereby increasing audit risk.

4. Customs Declaration

Core assessment: The customs declaration is the “final legal document” in import and export operations and constitutes the core basis for cross-verification by Thai Customs and the tax authorities, particularly with respect to import VAT deduction.

Proof of legality: Issued by the Thai Customs Department, it certifies that the goods have been legally imported or exported.

VAT deduction: In Thailand, the customs declaration is the sole legally recognized document for claiming import VAT credits.

Data verification: Customs and tax authorities rely on it to cross-check information on commercial invoices and bills of lading, ensuring the integrity and consistency of the data chain.

Risk alert: Information stated on the customs declaration must fully correspond with the actual transaction and payment records; any discrepancy may result in denial of VAT credits and the imposition of penalties.

II. Tax Documents Directly Affecting Costs and VAT Deduction

Conclusion: These documents directly affect an enterprise’s actual operating costs and tax burden. Proper management of these documents is critical for cost reduction and risk mitigation.

1. Customs Duty Payment Certificate

Core assessment: The customs duty payment certificate constitutes evidence that an enterprise has lawfully fulfilled its tax obligations and is an integral component of the cost structure of goods.

Cost composition: Customs duties form part of the cost of goods and may be capitalized as inventory or fixed asset costs.

Proof of compliance: It demonstrates that customs duties have been lawfully paid to customs authorities, thereby avoiding challenges from tax authorities.

Avoidance of duplication: It is necessary to verify that duties have been genuinely paid and to prevent double counting in financial records.

What I often state directly to clients is: “The customs duty payment certificate is the ‘legal label’ of your goods cost.”

2. Import VAT Payment Certificate

Core assessment: The import VAT payment certificate is the decisive instrument enabling enterprises to claim import VAT credits in Thailand, and its importance is self-evident.

Sole basis: It is the only legally recognized basis for claiming VAT credits at the import stage.

Tax risk: If this certificate cannot be provided, tax authorities may disallow VAT credits even if the goods were genuinely imported, and may pursue additional tax and penalties.

Cost impact: Non-creditable import VAT will directly increase an enterprise’s operating costs.

What I often state directly to clients is: “The import VAT payment certificate is key to cost savings when doing business in Thailand.”

3. International Freight and Related Service Invoices

Core assessment: Invoices for freight and related services are key components of landed cost, and their tax treatment directly affects VAT creditability and profit calculation.

Cost components: These include ocean freight, air freight, domestic transportation within Thailand, and customs declaration and clearance service fees.

VAT treatment: It must be determined whether invoices include 7% VAT and whether such VAT is creditable as input tax.

Cost allocation: Such costs should be appropriately capitalized into inventory to ensure accurate cost accounting.

Risk alert: Different types of expenses must be clearly distinguished to avoid VAT credit errors or inaccurate cost calculations.

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III. Thai Foreign Exchange and Cross-Border Fund Compliance Documents

Conclusion: Compliance in cross-border capital flows constitutes a “lifeline” for enterprises operating in Thailand, and these documents are critical to proving the legality of funds.

1. Bank Payment Slip (TT / SWIFT)

Core assessment: Bank payment slips serve as definitive evidence of cross-border fund movements, demonstrating that transactions genuinely occurred and that funds flowed lawfully.

Fund traceability: They demonstrate the source and destination of funds and constitute core evidence of cross-border payment compliance.

Transaction authenticity: They corroborate the authenticity of transactions and form a closed evidentiary loop with contracts and invoices.

Mandatory document: In tax inspections, audits, and M&A due diligence, bank statements are invariably subject to review.

What I often state directly to clients is: “The bank payment slip is the ‘financial identity card’ of cross-border transactions.”

2. Foreign Exchange Declaration Documents (FET / FX Form)

Core assessment: When cross-border funds reach specified thresholds, foreign exchange declaration documents evidence an enterprise’s fulfillment of foreign exchange control obligations.

Reporting obligation: Enterprises are legally required to declare foreign exchange transactions when amounts meet the reporting thresholds set by the Bank of Thailand.

Proof of compliance: Retention of foreign exchange declaration documents demonstrates compliance with foreign exchange regulations.

Focus of review: These documents are frequently requested during tax inspections, bank reviews, audits, or due diligence.

Risk alert: Failure to declare as required or missing documentation may result in penalties imposed by foreign exchange regulators.

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IV. Contracts and Internal Financial Documents: The “Deep-Water Zone” of Thai Tax Audits

Conclusion: These documents bridge internal management and external compliance and are essential for tax authorities to understand an enterprise’s operational logic.

1. Import and Export Contracts (Sales / Purchase Contracts)

Core assessment: Contracts constitute the legal blueprint of all transactions and serve as an important basis for tax authorities to assess transaction reasonableness.

Transaction authenticity: They prove the genuine existence of transactions and form the logical starting point for all subsequent documentation.

Pricing reasonableness: They define pricing mechanisms, which are particularly critical in related-party and transfer pricing reviews.

Clear allocation of rights and obligations: They delineate the respective rights and obligations of buyers and sellers.

Risk alert: Ambiguous or incomplete contractual terms may lead tax authorities to question the commercial substance of transactions.

2. Internal Financial and Inventory Management Documents

Core assessment: Internal documents reflect the rigor of internal management and serve as important references for tax authorities in assessing the reliability of accounting data.

Accounting vouchers: They record each economic transaction and constitute the foundation of financial accounting.

Inventory subsidiary ledgers: They detail inventory inflows, outflows, and balances, ensuring consistency between records and physical stock.

Cost allocation schedules: They reasonably allocate costs, affecting product costing and profitability.

Reconciliations and stocktakes: Monthly reconciliations and inventory counts substantiate the accuracy of inventory data.

Risk alert: Weak internal logic or data inconsistencies may trigger comprehensive tax audits.

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V. Supplementary Documents for Common Special Scenarios in Thai Enterprises

Conclusion: For specific business scenarios, enterprises must prepare and retain additional documents to meet more complex compliance requirements.

What I often state directly to clients is: “If your enterprise is involved in BOI incentives, special product regulations, or re-export arrangements, you must prepare the relevant supplementary documents in advance. These documents serve as your ‘pass’ to access policy incentives or to mitigate specific regulatory risks. In Thailand, ‘special treatment’ is predicated on ‘special documentation being properly prepared.’”

Conclusion: Building a “Logical Closed Loop” for Import and Export Compliance

In Thailand, the key to import and export financial compliance does not lie in the sheer number of documents collected, but in whether those documents collectively form a complete, rigorous, and explainable “logical closed loop.”

Based on TMA GROUP’s practical experience, the following four core elements must remain highly consistent at all times:

Contracts → Commercial Invoices → Customs Declarations → Bank Statements

Only when this closed loop is clear, accurate, and supported by a strong evidentiary chain can an enterprise achieve long-term, stable, and secure operations amid the stringent scrutiny of Thai customs, tax authorities, and auditors.

This is not merely a matter of compliance, but the foundation for sustainable and resilient development in the Thai market.

TMA GROUP, your compliance partner in Thailand.