CO Form S (Certificate of Origin – Form S) is a preferential certificate of origin issued for goods exported from Vietnam to Laos.
It enables Vietnamese exporters to enjoy special tariff preferences under the Vietnam–Laos Bilateral Trade Agreement.

This article explains what CO Form S is, its purpose, documentation requirements, and application procedure — along with what to do if your CO is delayed or contains errors.

>> Read More: Shipping Goods to Laos

What is CO Form S?

What is CO Form S?

A Certificate of Origin (CO) is an official document certifying the origin of exported goods, issued by a competent authority.
Each CO type applies to a specific trade agreement or destination market, such as:

• Form D:  For intra-ASEAN trade
  
• Form E: For exports to China
  
• Form AJ: For exports to Japan
  
• Form S: For exports from Vietnam to Laos
  

CO Form S certifies that the goods are of Vietnamese origin, qualifying them for import duty exemptions or reductions when entering Laos.

The Role and Importance of CO Form S

For Exporters

• Eligible for preferential tariff rates under the Vietnam–Laos trade agreement
• Enhanced price competitiveness in the Lao market
• Minimized customs risks — avoid shipment rejection, delays, or tax penalties 

For Authorities

• Helps prevent trade and origin fraud
  
• Supports accurate trade statistics between the two countries
  
• Serves as a basis for trade defense measures (anti-dumping, subsidy control, etc.)
  

>> Read More: What Are CO and CQ? Why Crucial in International Trade?

How to Fill Out CO Form S

When applying, exporters must complete the CO Form S accurately. Below is the field-by-field guide:

Documents Required for CO Form S Application

Documents Required for CO Form S Application

Exporters must prepare a complete application dossier including:

Export Documents

• CO Application Form (as per VCCI or MOIT format)
  
• Record Sheet (VCCI HCM template)
  
• Completed CO Form S (1 original + 3 copies)
  
• Export customs declaration
  
• Commercial invoice (certified copy)
  
• Bill of Lading (B/L), Air Waybill (AWB), or equivalent transport document
  

>> Read More: Bill of Lading (B/L) and Sea Waybill: Key Documents in Maritime Shipping

Proof of Origin Documents

• Detailed product list meeting origin criteria
  
• Declaration of origin from manufacturer or supplier
  
• Domestic purchase invoices for local materials
  
• Sales contract
  
• Export license (if applicable)
  
• Import declaration for raw materials
• Other supporting documents if required

CO Form S Application Procedure

Step 1 – Online submission via eCoSys (electronic CO system)

• Log in to the online CO system
  
• Fill in the CO application form
  
• Upload all required documents (scanned copies)
  

Step 2 – Automatic CO number issuance

The system assigns a provisional CO number; applicants can still edit the dossier before official submission.

Step 3 – Submit hard-copy documents

Send printed documents to VCCI or another authorized issuing authority.

Step 4 – Document verification

Authorities review the dossier:

• If incomplete → request revisions or additional documents
  
• If valid → proceed to approval
  

Step 5 – Approval and issuance

VCCI officers review, sign, and issue the official CO Form S, which exporters then submit to customs and importers in Laos.

CO Form S Issuance Timeline

CO Form S Issuance Timeline

• Standard processing time: Within 3 working days after receiving a complete and valid dossier.
  
• Extended cases: Up to 5 working days if a factory inspection is required.
  

 Tip: Submit your CO application at least 3 days before shipment to avoid the issue of “CO Form S issued after 3 days of vessel departure,” which may render it invalid for tariff preferences at the importing customs.

Frequently Asked Questions

Who issues CO Form S?
→ Typically issued by the Vietnam Chamber of Commerce and Industry (VCCI) or the Ministry of Industry and Trade (MOIT).

Is CO Form D from Singapore the same as Form S?
→ No. Form D applies to intra-ASEAN trade, while Form S is exclusive to Vietnam–Laos bilateral trade.

What if the CO is issued late?
→ Exporters may request post-issuance or submit a written explanation to the importing customs authority. However, it is always best to apply before shipment departure.

Vietnam–Laos Cargo Transportation Services by KFLV

Vietnam–Laos Cargo Transportation Services

Applying for C/O Form S is not just an administrative step — it is a crucial requirement for Vietnamese exporters to enjoy preferential tariffs when trading with Laos.
Even a minor mistake in the application or rules of origin can lead to losing tariff benefits, customs delays, or unexpected storage costs.

King Freight Logistics Vietnam (KFLV) provides end-to-end transportation and documentation support to help businesses export to Laos with speed and accuracy:

• Guidance on preparing documents correctly.
• Full support throughout the entire process — including customs clearance and delivery scheduling.
• Assistance with post-issuance or re-issuance cases when unexpected issues arise.
• Cost and time optimization to help businesses fully leverage Vietnam–Laos tariff preferences.

Contact us at +84 (0) 938 188 796 or cs1@hcm.kfkingfreight.com for detailed consultation and fast support, ensuring smooth clearance and maximum tariff benefits for your cargo.