Key Takeaways

• A Customs Declaration is an essential document used to declare shipment details to the Customs Department for import and export procedures.
• Today, most customs declarations are submitted electronically through customs systems.
• Key information, including HS Code, Quantity, Weight, Customs Value, Country of Origin, and required Permits, must be verified for accuracy before submission.
• A Commercial Invoice, Packing List, and Transport Document are important supporting documents used to prepare a customs declaration.
• A Customs Declaration is not the same as a Bill of Lading (B/L) or Air Waybill (AWB), as each document serves a different purpose.

When importing goods from overseas or exporting goods from Thailand, businesses must complete customs procedures and accurately declare shipment information. One important part of this process is the Customs Declaration.

Although the Thai term for a Customs Declaration may sound like it refers to a single sheet of paper, Thailand's customs procedures are now primarily based on electronic data submission. Once the information has been checked and accepted by the system, a declaration number is issued for use in subsequent steps.

Businesses should therefore understand what information must be prepared, who submits the declaration, and which errors can delay Customs Clearance.

What Is a Customs Declaration?

A Customs Declaration is information submitted by an importer, exporter, or appointed representative to the Customs Department to declare the details of goods for import or export procedures.

The information in a Customs Declaration may include:

• Importer or exporter
• Seller and buyer
• Commodity type
• HS Code
• Quantity of goods
• Number of Packages
• Weight
• Goods value
• Customs Value
• Country of Origin
• Origin and destination countries
• Transport Document
• Preferential tariff treatment
• Permit or License
• Applicable taxes and duties

This information must be consistent with the goods and the Shipment's commercial documents because the Customs Department uses it to check Classification, Valuation, Tax, and product requirements.

What Is an Import Customs Declaration?

An Import Customs Declaration is used to declare goods imported into Thailand to the Customs Department.

For general imports, the importer or its representative prepares the import declaration data in the format specified by the Customs Department and submits it to the customs system electronically.

After the system checks the information, if it meets the required conditions, an import declaration number is issued for subsequent steps, such as:

• Payment of duties and taxes
• Permit verification
• Customs inspection and release
• Release of goods from customs control

If the goods are regulated by other agencies—for example, food, cosmetics, electrical appliances, plants, animals, or other products subject to specific laws—relevant permits or additional information must also be prepared before Customs Clearance.

What Is an Export Customs Declaration?

An Export Customs Declaration is used to declare goods that will be exported from Thailand.

The exporter or its representative submits the export declaration data to the customs system. Once the information is complete and correct, the system issues an export declaration number for customs procedures and the movement of goods to the point of export.

The information must be consistent with the actual Shipment, including:

• Exporter
• Consignee
• Invoice
• Description of Goods
• HS Code
• Quantity
• Package
• Weight
• Value
• Country of Destination
• Transport Information
• Permit, where applicable

For goods subject to export controls, the required permits from the relevant agencies must be obtained before export.

How Does a Customs Declaration Differ from a Bill of Lading?

These are different types of documents with different purposes.

Customs Declaration

Used to declare information to the Customs Department for import and export procedures.

Bill of Lading (B/L)

A Transport Document associated with sea freight. It records details of the goods received for transportation and Shipment information under the applicable transport terms.

A Bill of Lading may therefore be one of the documents or information sources used when preparing an import Customs Declaration, but it is not itself a Customs Declaration.

Is an Air Waybill the Same as a Customs Declaration?

No, they are different.

An Air Waybill (AWB) is an air transport document, while a Customs Declaration is a declaration submitted to customs.

For example, a single Air Shipment may involve:

• Commercial Invoice
• Packing List
• Air Waybill
• Export Customs Declaration in Thailand
• Import Customs Declaration in the destination country

These documents are related, but each serves a different purpose.

Suggested Internal Link: What Is Air Cargo? What Types of Goods Are Suitable for Air Freight?

What Documents Are Required for an Import Customs Declaration?

The actual documents required depend on the goods and Shipment, but commonly used documents include:

• Commercial Invoice
• Packing List
• Bill of Lading or Air Waybill
• Insurance Document, where applicable
• Certificate of Origin, if preferential tariff treatment is claimed
• Import Permit for controlled goods
• Product Specification
• Ingredients or composition information, depending on the product
• Other documents requested by the relevant agency or Customs Department

Having only an Invoice and Packing List does not necessarily mean the documentation is complete for every type of product, as controlled goods may have additional Requirements.

What Documents Are Required for an Export Customs Declaration?

For exports, businesses should prepare basic documents such as:

• Commercial Invoice
• Packing List
• Product details
• HS Code
• Transport Information
• Export Permit, if the goods are controlled
• Product-specific certificates or documents, where applicable
• Certificate of Origin, if required by the Buyer or trade preferences

If the Shipment uses a Letter of Credit, check the L/C Requirements as well, because Shipping Documents may need to be prepared in strict accordance with the specified terms.

Suggested Internal Link: What Is a Letter of Credit (L/C)? Types and Benefits in Import–Export Transactions

Why Is HS Code Important for a Customs Declaration?

The HS Code is important for classifying goods in customs procedures.

For imports, the HS Code can affect:

• Import Duty
• Import measures
• Permit requirements
• FTA preferences
• Tax
• Statistical Code

HS Code selection should not be based on a general product name alone. Relevant details must be considered, such as:

• Material
• Composition
• Function
• Intended use
• Specification
• Product characteristics

Using an incorrect HS Code may result in incorrect duty calculations or a Permit that does not match the actual goods.

Suggested Internal Link: Why Is HS CODE Important?

Why Is Customs Value Important for an Import Customs Declaration?

For imports, the value used to assess duties and taxes must be determined according to customs valuation rules.

The amount paid to the Supplier is not necessarily the final figure used to calculate taxes in every case.

Relevant information may include:

• Goods price
• Freight
• Insurance
• Currency
• Incoterms
• Costs that must be included under the applicable rules

Before preparing an import Customs Declaration, Customs Value should therefore be checked alongside the HS Code.

Suggested Internal Link: What Is Customs Value (CIF)? 4 Steps to Calculate Import Taxes

How Is a Certificate of Origin Related to a Customs Declaration?

A Certificate of Origin or other proof of origin may be used to claim preferential tariff treatment if the goods meet the requirements of the relevant FTA.

The following should be checked together:

• HS Code
• Country of Origin
• Rules of Origin
• FTA
• Proof of Origin
• Applicable preferential tariff rate

If preferential tariff treatment is claimed, the origin evidence must be consistent with the Shipment and the information declared to Customs.

Suggested Internal Link: What Is a Certificate of Origin? Types of C/O and Required Documents

What Are the Steps for Preparing an Import Customs Declaration?

The general process for a Commercial Shipment can be divided into the following steps:

1. Prepare Product Information and Documents

Check the Invoice, Packing List, Transport Document, HS Code, Country of Origin, and Permit.

2. Calculate Import-Related Information

Check Customs Value, Duty Rate, Tax, and applicable FTA preferences.

3. Prepare and Submit the Customs Declaration

The importer or its representative submits the import declaration electronically in accordance with the Customs Department's standards.

4. System Verification

If the information is correct, the system returns a declaration number and the relevant procedures can continue.

5. Pay Duties and Taxes

The importer pays Duty, VAT, or other taxes applicable to the product.

6. Customs Inspection and Release

The Shipment may be subject to inspection under the Customs Department's risk-management system.

7. Collect the Goods from the Customs-Controlled Area

Once all customs procedures and requirements have been completed, the goods can be released for onward Delivery.

The actual process may vary depending on the Mode of Transport, Customs House, and type of goods.

What Are the Steps for Preparing an Export Customs Declaration?

The main export process includes the following steps:

1. Prepare Documents and Check the Goods

Check the Commercial Invoice, Packing List, HS Code, and Permit, where applicable.

2. Submit the Export Customs Declaration

The Exporter or its representative submits the data electronically to the customs system.

3. Receive the Declaration Number

Once the information passes the system checks, an export declaration number is issued.

4. Arrange the Movement of Goods

Prepare the information needed to move the goods to the Port, Airport, or Border, depending on the Mode of Transport.

5. Customs Inspection, Where Applicable

If the Shipment is selected for inspection, the required steps must be completed before export.

6. Load and Export the Goods

After the relevant procedures have been completed, the goods can be loaded onto a vessel, aircraft, or truck, or transported out of the Kingdom through a border checkpoint.

Who Can Submit a Customs Declaration?

In general, a Customs Declaration may be handled by:

• Importer
• Exporter
• Customs Broker
• An appointed representative acting in accordance with the applicable requirements

Businesses conducting customs procedures must have the required status and registration information with the Customs Department in accordance with the prescribed process.

Businesses that do not handle customs procedures themselves may appoint a Customs Broker or Logistics service provider to help prepare and submit the information.

Suggested Internal Link: What Is the Customs Paperless System? An Easy Guide to Importer–Exporter Registration

How Is e-Customs Related to a Customs Declaration?

Today, Customs Declaration data is primarily submitted electronically to the Customs Department's computer system.

This reduces the need for paper documents in many parts of the process and allows information from businesses, representatives, and the customs system to be connected.

However, Paperless does not mean that original supporting documents are no longer needed.

Businesses still need relevant information or evidence, such as:

• Invoice
• Packing List
• Transport Document
• Permit
• Certificate
• Product Information

These are used to prepare and verify the Customs Declaration data.

Must the Invoice and Customs Declaration Information Match?

Key information should be consistent across the documents.

For example:

• Seller / Buyer
• Description of Goods
• Quantity
• Unit
• Value
• Currency
• Country of Origin
• Incoterms
• Package

This does not mean every field must be identical character by character, because a Customs Declaration uses its own data format. However, the details must not conflict with the actual Shipment.

Why Is the Packing List Important for a Customs Declaration?

A Packing List provides packing details, such as:

• Number of Packages
• Package type
• Quantity
• Gross Weight
• Net Weight
• Dimensions
• Shipping Marks, where applicable

This information helps the Customs Broker verify the Shipment details and prepare the declaration more accurately.

If the actual shipment contains 20 Cartons but the Packing List states 18 Cartons, the document should be corrected before customs procedures begin.

Suggested Internal Link: What Are Shipping Marks and Why Are They Important in International Shipping?

What Problems Can Incorrect Customs Declaration Information Cause?

Incorrect information can cause anything from delays to additional costs, depending on the nature of the error.

Examples include:

• Incorrect HS Code
• Incorrect Quantity
• Incorrect Weight
• Incorrect Value
• Incorrect Country of Origin
• Incorrect Permit
• An overly broad Description of Goods
• Incorrect Transport Document Reference
• Claiming FTA preferences without meeting the requirements

These issues may require the business to:

• Amend the information
• Submit additional documents
• Undergo a goods inspection
• Have duties reassessed
• Wait longer for Clearance
• Pay additional Storage Charges

It is therefore better to verify the information before submitting the declaration than to wait until the Customs Process has started to correct it.

Can a Customs Declaration Be Amended?

There may be procedures for requesting amendments, depending on the circumstances. The process and required documents depend on factors such as:

• Which information is incorrect
• The current stage of customs procedures
• Whether the goods have already been released
• Whether the error affects taxes
• Whether the error relates to a Permit

An amendment after submission should therefore not be treated as a routine step.

The best approach is to Review the information in the Invoice, Packing List, and Transport Document before submitting the Final data.

How Is a Customs Declaration Related to Import Taxes?

The information in an import Customs Declaration is essential for calculating and declaring duties and taxes.

Important factors include:

• HS Code
• Customs Value
• Country of Origin
• Duty Rate
• FTA
• Excise Tax, depending on the product
• VAT

Import tax calculation does not start with the Freight price alone. Classification and Customs Value must first be checked for accuracy.

Are Customs Declarations Required for Air, Sea, and Road Shipments?

Customs procedures apply to imports and exports across various Modes of Transport, including:

• Air Freight
• Sea Freight
• Road / Cross Border

However, Manifest requirements, Transport Documents, customs release points, and cargo movement procedures differ depending on the Mode and customs checkpoint.

Therefore, Air Cargo procedures should not be applied directly to every step of Sea Freight.

Who Prepares the Commercial Invoice and Customs Declaration?

The Commercial Invoice is generally issued by the Seller or Exporter to record the commercial transaction.

A Customs Declaration, on the other hand, is prepared to declare information to Customs. The importer, exporter, or Customs Broker may handle this process, depending on the applicable procedures.

These are two separate documents, but the Invoice is an important source of information for preparing the Customs Declaration.

What Information Should Be Prepared Before a Customs Declaration Is Filed?

To help a Customs Broker or service provider review the information efficiently, prepare at least the following:

• Commercial Invoice
• Packing List
• Product Description
• Product photos
• HS Code, if already verified
• Material / Ingredients, depending on the product
• Product Specification
• Country of Origin
• Quantity
• Unit
• Gross Weight
• Net Weight
• Number of Packages
• Incoterms
• Transport Document
• Permit / License
• Certificate of Origin, if claiming FTA preferences

The clearer the Product Description, the easier it is to check the HS Code and applicable Requirements compared with providing only a broad product name.

Frequently Asked Questions About Customs Declarations (FAQ)

Are a Customs Declaration and a Bill of Lading the Same Document?

No. A Customs Declaration is used to declare information to Customs, while a Bill of Lading is a sea transport document.

Must the importer prepare the Customs Declaration personally?

Not necessarily. A Customs Broker or relevant appointed representative may handle the customs procedures on the importer's behalf, subject to the applicable requirements.

Is an Invoice alone sufficient to prepare a Customs Declaration?

Not always. Other information may be required depending on the Shipment, such as a Packing List, Transport Document, Permit, C/O, or Product Specification.

Are Customs Declarations completed on paper or online?

Today, the general process primarily uses electronic submission of Customs Declaration data to the Customs Department's system.

Does an incorrect HS Code affect a Customs Declaration?

Yes. The HS Code is linked to duty rates, import and export measures, and Permit requirements. Incorrect classification may require amendments and a reassessment of taxes or other requirements.

Document Preparation and Customs Clearance Services with CPL INTER

CPL INTER provides international shipping services by air, sea, and road, along with Shipping Documents preparation and import–export customs procedures according to the Shipment's Service Scope.

Before importing or exporting, businesses can prepare the product name, photos, Commercial Invoice, Packing List, dimensions, weight, value, Country of Origin, and relevant Permit documents. The CPL INTER team can help conduct an initial review before customs procedures and transportation begin.

Tel: 02-519-4426 / 091-519-4426 LINE: @cplinter

Written by: CPL Inter Logistics Operations Team, specialists in international freight transportation and customs procedures, with more than 15 years of experience and an internationally recognized ISO 9001:2015 quality management system.