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Shipper’s Letter of Instruction (SLI)

Glossary Shipping

Shipper’s Letter of Instruction (SLI)

A Shipper’s Letter of Instruction (SLI) is a key document used in international shipping. It is issued by the exporter (the shipper) and provides clear written instructions to the freight forwarder or carrier responsible for moving the goods. The SLI outlines how the cargo should be handled, transported, and documented. It serves as both an authorisation and a guide, helping ensure that all parties involved follow the correct process.

The shipper is responsible for preparing and submitting the SLI. This responsibility includes providing accurate information about the shipment, including commercial, logistical, and regulatory details. The freight forwarder then uses the SLI to complete the necessary export documentation, book transport, and submit customs declarations where required.

Purpose of the Shipper’s Letter of Instruction

The SLI helps bridge the communication gap between the exporter and the freight forwarder. It ensures that:

  • Goods are shipped according to the exporter’s preferences and requirements
  • All parties understand their roles and responsibilities
  • Errors, delays, and compliance issues are minimised

By using an SLI, exporters retain control over how their goods are managed during export, while freight forwarders gain the information needed to act efficiently and legally on their behalf.

What the Shipper’s Letter of Instruction Includes

A typical Shipper’s Letter of Instruction contains:

  • Shipper’s and consignee’s contact details
  • Description of goods being exported (including weight, dimensions, and packaging type)
  • Incoterms (e.g. FOB, CIF) indicating the terms of delivery
  • Export licence or authorisation details (if applicable)
  • Instructions for freight booking and routing
  • Details of the mode of transport (air, sea, road, or rail)
  • Customs information and commodity codes
  • Insurance requirements
  • Authorisation for the forwarder to sign export documentation on the shipper’s behalf

Accurate completion of the SLI is crucial, as incorrect or missing information can lead to delays, penalties, or non-compliance with export laws.

Download a SLI sample here

Who Is Responsible?

The exporter (shipper) is legally and operationally responsible for providing the Shipper’s Letter of Instruction. This includes:

  • Supplying complete and accurate data about the goods and destination
  • Ensuring the instructions comply with export regulations
  • Confirming that the forwarder is authorised to act on their behalf

The freight forwarder is responsible for carrying out the instructions within the SLI. This may include:

  • Booking cargo space with carriers
  • Preparing transport and customs documents
  • Filing export declarations
  • Coordinating logistics from the point of origin to final delivery

The SLI allows the forwarder to act as the shipper’s agent, but only within the scope of the instructions provided.

We are friendly, easy to work with, honest and we do not charge the earth.

At Barrington Freight, we specialise in making your importing and exporting straightforward. From customs clearance to finding the right commodity codes, our expert team is here to assist. Don’t let the complexities of global trade hold you back. Reach out to Barrington Freight for efficient and reliable shipping solutions.

Is the SLI Legally Required?

The Shipper’s Letter of Instruction is not a legal requirement in all cases, but it is considered industry best practice. Many freight forwarders will request one before handling a shipment. When goods are being exported from the UK under a formal customs declaration, the SLI is often used to document the shipper’s consent for the forwarder to submit declarations on their behalf.

Using an SLI also provides a paper trail that can help resolve disputes, confirm responsibilities, and support compliance audits.

Benefits of Using a Shipper’s Letter of Instruction

  • Provides clear direction for freight forwarders
  • Helps avoid misunderstandings or incorrect shipments
  • Supports customs compliance
  • Streamlines the export process
  • Protects the shipper by documenting authorisation and terms

Final Notes

To complete a Shipper’s Letter of Instruction accurately, exporters should use a clear and structured template and verify all information before submission. The SLI should be signed and dated by an authorised person within the exporting company.

For a detailed walkthrough of how to complete an SLI, visit: How to Complete a Shipper’s Letter of Instruction.

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About the Author

Simon Poole began his career in production planning, quickly rising to manage 24-hour manufacturing lines and oversee a team of 140 staff. In 2007, he joined Barrington Freight, where he brought his operational expertise into the logistics sector. Appointed Operations Director in 2021, Simon now leads all day-to-day operations, including sea, air and European freight, working closely with clients and partners worldwide.

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Sam McGowan
17 August 2026
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Fantastic Service. Lee organised a last minute pickup from Sweden back to England. The shipment was under Carnet. Very good professional service at a competitive rate! I will be using them again.
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Louise Ponsford
13 August 2026
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Excellent service from start to finish. Simon at Barrington Freight handled our crate of mechanical machine parts from the UK to Canada with exceptional care, keeping us informed throughout. His Canadian agent also arranged customs clearance, making the entire process straightforward and stress-free. Highly recommended.
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Proydohi
6 August 2026
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I would like to thank the entire Barrington Freight team for their professional work and assistance in organizing the shipment of my cargo to the UK. I will definitely use their services again. Highly recommended.
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Mike Yeo
23 July 2026
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The team at Barrington Freight were brilliant, leading us through the minefield that is exports to the EU. Nothing was too much trouble and we received immediate answers to all our many questions. We will definitely use them again and recomend them to anyone.
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Courtney Freeman
22 June 2026
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We had a fantastic experience importing our goods from Florida and honestly couldn’t fault the service. The quote was quick and easy, booking was straightforward and everything was handled smoothly from start to finish. As this was our first import we needed a bit of guidance along the way but Simon was brilliant. He took care of everything, kept us updated throughout and was always on hand to answer our questions. What seemed like a complicated process was made incredibly simple and stress free. The customer service was excellent, communication was spot on and our shipment arrived without any issues. We wouldn’t hesitate to use them again and would highly recommend them to anyone looking for a reliable freight forwarder. Thanks again for making our first import such a positive experience!
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Katie r Smith
18 June 2026
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Simon looked after our air freight import from China and provided an excellent service throughout. The shipment arrived safely and quicker than expected, with clear communication at every stage. We were very pleased with the experience and will definitely use Simon and his team at Barrington Freight again in the future.
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Phil Holloway
18 June 2026
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We needed to get a shipment out to the USA quickly and Simon made the whole process far easier than we expected. Communication was straightforward, we were kept updated throughout, and everything arrived on time without any issues. It's refreshing to deal with someone who knows exactly what they're doing and gets things done. We'd happily use Simon again for future air freight shipments.
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James Roberts
15 June 2026
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Matt really looked after us and made our shipment completely stress free, I will be using the services of Barrington Freight for all my overseas shipments from now on. Thanks Matt, great service
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General Enquiries
23 April 2026
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We have had consistently excellent service from Barrington Freight. Our main contact, Joshua Armstrong, is always incredibly helpful and reliable. He goes above and beyond to ensure everything runs smoothly. Communication is clear and prompt and any issues are handled quickly and efficiently. It's reassuring to know that everything is in safe hands from start to finish. I would highly recommend Barrington Freight to anyone looking for dependable and professional logistics partner.
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George Dunster
10 April 2026
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We had a time-critical air freight shipment coming in from China to the UK and Simon was a huge help in getting it over the line. Right before arrival, an issue came up due to a mistake from the airline, which could have turned into a real headache. Simon picked it up straight away, dealt with it quickly and managed to sort everything without any extra costs on our side. Really solid support throughout and easy to deal with, especially given the urgency. Another great job by Barrington Freight - we’ll definitely be using them again!
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Euphoric Bedding
1 April 2026
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Good service during a turbulent global shipping period. Special thanks goes to Lee for his efficiency and proactive updates and for rescheduling a delivery in less than 24hrs when the haulage company didn’t read their own paperwork and sent a lorry without the requested tail lift. Highly recommended.
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The Greens
5 March 2026
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Great communication, competitive and efficient delivery
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Shannon Sharp
4 March 2026
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We’ve worked with Barringtons for the past two years, and the service has been excellent throughout. Every shipment has been handled with great care and real personal attention. A special thanks to Simon, who has been outstanding—always professional, responsive, and a pleasure to work with. Highly recommended!
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Peter Aylmore
4 March 2026
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Barringtons always have worked well for us . They are efficient with the import / export paperwork . Always answer very quickly with both quotations and any issues. prices always competitive , indeed recently saved our customer a considerable sum on an export job. Truly excellent service
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Paul Newby
4 March 2026
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As first time importers, we are very happy with the service Barrington provided. Sean guided us through the whole process and was very patient with our questions. We will be happy to use them again for future shipments

We’re friendly, easy to work with, honest and we don’t charge the earth.

For advice and information on shipping time from China to the UK, call 01268 525444 or email us today.

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