GlossaryEN1 min readUpdated: Jun 26, 2026

Shipper's Letter of Instruction (SLI)

Shippers and exporters use the Shipper's Letter of Instruction (SLI) to provide their freight forwarder or airline with all the information needed to process an air cargo shipment.

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Last updated: 26 June 2026Published: 27 January 2026

Source: https://www.iata.org

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Definition & Explanation

Shippers and exporters use the Shipper's Letter of Instruction (SLI) to provide their freight forwarder or airline with all the information needed to process an air cargo shipment. It is the primary source document for preparing the Air Waybill (AWB), covering consignee details, commodity description, weight, declared value, and charge responsibility (prepaid or collect). Special handling requirements, insurance instructions, and hazardous goods declarations in line with IATA regulations are recorded here as well. The SLI is not a contract of carriage but an authorisation: it empowers the forwarder to act on the shipper's behalf and issue the relevant transport documents. A fully completed SLI cuts down on queries and speeds documentation turnaround considerably.

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Recommended format: Source: Freight Academy – Shipper's Letter of Instruction (SLI) (https://www.freight-academy.com/en/glossary/shippers-letter-of-instruction-sli), accessed 2026-11-08
APA style: Freight Academy Editorial Team. (2026). Shipper's Letter of Instruction (SLI). Freight Academy. https://www.freight-academy.com/en/glossary/shippers-letter-of-instruction-sli
BibTeX: @misc{shippersletterof2026, title = {Shipper's Letter of Instruction (SLI)}, author = {{Freight Academy Editorial Team}}, year = {2026}, url = {https://www.freight-academy.com/en/glossary/shippers-letter-of-instruction-sli}, note = {Freight Academy, accessed 2026-11-08} }

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