1. Introduction: Why SLI Matters in Modern Shipping
In global trade, every detail in documentation can determine whether a shipment flows smoothly or gets delayed at customs. One such critical document is the Shipper’s Letter of Instruction (SLI). Understanding what is SLI in shipping is essential for exporters, importers, and freight forwarders who want to ensure seamless cargo handling and legal compliance.
The SLI acts as the communication bridge between the shipper and the freight forwarder, instructing exactly how goods should be handled, declared, and transported. Without it, the shipping process can face unnecessary slowdowns, penalties, or even cargo rejection.
2. What Is SLI in Shipping?
The Shipper’s Letter of Instruction is a document prepared by the exporter to give precise details to the freight forwarder or carrier about an export shipment.
It typically includes:
- Exporter & consignee details
- Shipment description (weight, dimensions, packaging)
- Export license numbers (if applicable)
- Special handling instructions
- Declared value for customs
In short, what is SLI in shipping can be summed up as: your official instructions to ensure your goods are transported in compliance with trade regulations and contractual agreements.
3. Why Is SLI Important in International Freight?
Many countries require export declarations to be filed correctly before departure. The SLI helps freight forwarders prepare accurate Electronic Export Information (EEI) for U.S. Customs or equivalent agencies.
An SLI ensures that the transportation mode, routing, and service level (air, sea, road) match the shipper’s requirements.
It minimizes misunderstandings between the shipper and the freight forwarder, avoiding costly delays.
4. Key Components of an SLI
| Section | Details Provided | Why It Matters in Shipping |
|---|---|---|
| Shipper Information | Company name, address, contact person | Identifies export source |
| Consignee Information | Buyer’s name, address, country | Ensures delivery accuracy |
| Cargo Description | Commodity name, HS code, quantity, weight, packaging | Determines customs clearance |
| Export Control Data | License numbers, ECCN codes | Meets export law compliance |
| Special Instructions | Temperature control, hazardous materials notes | Ensures correct handling |
5. How to Fill Out an SLI Correctly
- Gather Export Details – Confirm buyer information, cargo specs, and Incoterms.
- Select the Mode of Transport – Air freight for speed, sea freight for cost-efficiency.
- Complete Export Control Information – Add licenses, control codes, and compliance references.
- Specify Special Handling Instructions – For perishable, fragile, or hazardous cargo.
- Sign and Date the Document – Authorize the freight forwarder to act on your behalf.
6. SLI in Air Freight vs. Sea Freight
- Air Freight: The SLI focuses heavily on weight, dimensions, and urgent delivery timelines.
- Sea Freight: The emphasis is on container type, cargo weight limits, and port handling instructions.
In both cases, knowing what is SLI in shipping ensures the correct transport documentation is submitted before cargo departure.
7. Common Mistakes to Avoid
- Leaving fields incomplete
- Providing vague cargo descriptions
- Missing license or compliance codes
- Not updating consignee contact details
Any of these can delay transportation and increase shipping costs.
8. The Role of Freight Forwarders in SLI Management
A professional freight forwarder doesn’t just transport goods—they ensure your documentation, including the SLI, meets legal and operational standards. At Taijie International Logistics, we help clients prepare and submit SLI documents efficiently, reducing the risk of shipment delays and customs holds.
9. Request a Quote for Your Next Shipment
Need expert help preparing your SLI and arranging international freight?
Our team ensures full compliance, competitive shipping rates, and smooth transport for your cargo.
Q1: Is SLI mandatory for all international shipments?
No, but it is strongly recommended, especially when export compliance regulations apply.
Q2: Can an SLI be submitted electronically?
Yes, most freight forwarders accept digital SLI submissions via email or online portals.
Q3: How long should I keep copies of my SLI?
For compliance, retain records for at least five years from the date of shipment.
Q4: Does SLI replace a Bill of Lading?
No, the SLI is an instruction document, while the Bill of Lading is a transport contract.