What Is a Shipping Instruction (SI), and What Information Does the Carrier Need?

For anyone shipping cargo by sea for the first time, the paperwork that piles up between confirming a booking and actually seeing a Bill of Lading in hand can feel opaque — several documents change hands, and it isn't always obvious which one does what. The Shipping Instruction (SI) is one of the least visible of these, precisely because it isn't a document a shipper ends up holding onto. It's an input, not an output: the form (paper or, more commonly now, submitted through a carrier's online portal or EDI system) that tells the carrier exactly what to write on the Bill of Lading it's about to issue.

That makes the SI, in practical terms, the single most consequential document in the whole booking-to-B/L sequence, even though it rarely gets discussed with the same weight as the B/L itself. Everything on the final shipping document — names, addresses, cargo description, weight — traces back to what was typed into the SI. Get it right, and the rest of the process is largely mechanical. Get it wrong, and the mistake propagates forward into a document that's far more expensive and disruptive to correct after the fact.

What a Shipping Instruction Actually Contains

An SI is structured around the same fields that will eventually appear on the Bill of Lading, because that's its entire purpose. At minimum, it covers:

• Shipper — the exporting party's full legal name and address, exactly as it should read on the B/L
• Consignee — the receiving party's name and address, or the words 'to order' (or 'to order of [bank]') if the B/L needs to be negotiable rather than made out to a named party
• Notify party — who the carrier or its agent should contact when the cargo arrives, if different from the consignee
• Container and seal numbers — for FCL shipments, plus the number and type of packages for LCL cargo
• Marks and numbers — the identifying marks stenciled or labeled on the actual cargo, matched to what's declared
• Description of goods — a commercial description sufficient to identify the cargo, generally aligned with the commercial invoice
• Gross weight and measurement — the shipment's weight and CBM, used both on the B/L and for the carrier's own manifest
• Freight payment terms — whether freight is prepaid or collect, and which party the carrier should invoice
• Special instructions — anything that doesn't fit the standard fields: dangerous goods classification details, temperature control requirements for reefer cargo, or specific instructions about how and to whom the original B/L should be released

A forwarder handling the shipment typically pulls most of this from the commercial invoice, packing list, and the underlying sales contract or letter of credit, then formats it into whatever template or online portal the specific carrier uses. Different carriers have different SI formats and different online systems, which is one reason a forwarder juggling several carrier relationships is doing real, non-trivial coordination work even for what looks like a routine data-entry task.

Where the SI Fits in the Booking-to-B/L Sequence

The SI sits at a specific point in a fixed sequence, and understanding that sequence explains why timing matters as much as content. First, the shipper or forwarder requests and receives a confirmed booking, which reserves space on a specific sailing and comes with a set of cut-off dates — for cargo delivery to the terminal, for the SI, and sometimes for a separate VGM (verified gross mass) declaration. Second, the shipper submits the SI before its specific cut-off, which is typically set earlier than the cargo cut-off so the carrier has time to process the data and prepare a draft. Third, the carrier (or its documentation team) drafts the Bill of Lading directly from the SI and, for most modern bookings, sends that draft back to the shipper or forwarder for review before final issuance. Fourth, once the draft is confirmed correct, the carrier issues the final B/L — either as an original paper document, a telex-release confirmation, or a seaway bill, depending on what was agreed.

The draft-review step is worth pausing on, because it's the shipper's last practical opportunity to catch an SI error before it becomes a Bill of Lading error. A shipper or forwarder that treats the draft B/L as a formality to rubber-stamp, rather than a genuine check against the original SI and the underlying commercial documents, gives up the least costly point in the whole process to fix a mistake.

SI, Booking Confirmation, and B/L Are Not the Same Document

Because all three documents circulate close together in time, it's easy to blur them into a single mental category of 'shipping paperwork.' They serve genuinely different functions. A Booking Confirmation is issued by the carrier at the start of the process and simply proves that space has been reserved on a specific sailing — it doesn't carry the level of cargo detail an SI does, and it isn't a document of title or evidence of a contract of carriage in the way a B/L is. An SI, as covered above, is the shipper's input to the carrier, never issued by the carrier itself, and carries no legal weight on its own — it's the data the B/L is built from, not a substitute for it. The Bill of Lading is the output: issued by the carrier after cargo is loaded and the SI has been processed, it serves as a receipt for the goods, evidence of the contract of carriage, and — if issued as a negotiable 'to order' document — a document of title that controls who can claim the cargo at destination.

The practical reason to keep these three straight is that each carries a different kind of risk if handled carelessly. Losing track of a Booking Confirmation risks losing the reserved space if a carrier needs proof of the booking. Submitting an SI late risks missing the sailing's documentation cut-off entirely, even if the cargo itself makes the vessel. And an inaccurate B/L — the end product of an inaccurate SI — risks a customs mismatch, a bank rejecting documents under a letter of credit, or a dispute over who's entitled to claim the cargo at the destination port.

Who Prepares the SI, and Who Stays Responsible for It

In practice, most shippers working through a freight forwarder don't fill in the carrier's SI form themselves — the forwarder does, pulling the required fields from the commercial invoice, packing list, and booking details the shipper already provided. That's a genuine convenience: the forwarder knows each carrier's specific SI format and portal, and consolidating that work with someone who handles it daily reduces the chance of a formatting mistake.

What doesn't change, regardless of who physically types the SI into a carrier's system, is where responsibility for the accuracy of the underlying data sits. A forwarder can only submit what the shipper gives it — if the shipper supplies an incomplete consignee address or a rounded-off weight figure, the forwarder has no way of knowing that's wrong unless it's flagged separately. This is why it's worth a shipper reviewing the SI, or at minimum the resulting draft B/L, itself rather than assuming the forwarder has independently verified every field. The forwarder is a conduit for accurate data, not a source of it.

The SI Cut-Off, and Why It's Earlier Than Shippers Expect

Every carrier sets its own SI cut-off — a deadline, usually stated as a specific date and local time, by which the shipping instruction must be submitted for that particular sailing. A common source of confusion is assuming this lines up with the cargo cut-off (the deadline for physically delivering cargo to the terminal or CFS). It usually doesn't: the SI cut-off is typically set a day or more before the cargo cut-off, precisely because the carrier needs time to process the data, generate a draft B/L, and circulate it for review before the vessel sails.

Missing the SI cut-off doesn't necessarily mean missing the sailing itself if the cargo is already booked and loaded, but it does tend to compress or eliminate the draft-review step described earlier, and it can push the shipper into whatever expedited or exception process the carrier uses for late submissions — which is rarely as smooth as the standard workflow. For a shipper working through a forwarder, one of the more useful habits is asking, at the time of booking, exactly when the SI is due — not assuming it shares a deadline with anything else on the shipment's document checklist.

What Happens When the SI Has an Error

An error caught during the draft-review step is the least costly kind to fix — it's usually just a matter of flagging the incorrect field to the carrier's documentation team before the final B/L is issued, at little or no cost. Once the final Bill of Lading has been issued, correcting the same error typically becomes a formal amendment process: the carrier requires a written correction request, sometimes supporting documentation proving the correct information, and — depending on the carrier and the nature of the error — an amendment fee. For an original paper B/L already in circulation (for example, sent to a bank under a letter of credit), correction can also mean physically recalling and reissuing the document, which adds real time to a process that may already be running against a payment or delivery deadline.

Some errors carry consequences beyond cost and delay. A misdescribed cargo or an incorrect HS-code-adjacent description can create a mismatch with the customs declaration filed at destination, triggering a hold or query. A wrong consignee name on a negotiable B/L can complicate who's able to claim the cargo. These are reasons the draft-review step deserves genuine attention rather than a quick glance — it's the one point in the sequence where a mistake is still cheap to fix.

Example

Consider a Thai exporter shipping a full container of processed food products to a buyer in South Korea, under a letter of credit that requires a negotiable Bill of Lading made out 'to order' of the buyer's bank. Once the forwarder confirms the booking, it prepares the SI using the commercial invoice and packing list the exporter has already finalized: the exact legal name and address of the consignee's bank for the 'to order' field, the notify party (the actual buyer, who needs to know when the cargo arrives even though the bank is named on the B/L), the container and seal numbers assigned at stuffing, the product description matched word-for-word to the invoice, and the gross weight and CBM confirmed after loading.

The forwarder submits the SI a day ahead of the carrier's cut-off, leaving a buffer in case anything needs correcting. When the draft B/L comes back, the exporter checks it specifically against the letter of credit's wording — because a bank reviewing documents under a letter of credit will reject a B/L that doesn't match the LC's requirements precisely, down to how the consignee field is phrased. A discrepancy caught here costs a quick correction request to the carrier. The same discrepancy caught only after the final B/L has already been couriered to the bank could mean a rejected document set and a delayed payment — which is exactly the gap in consequence that makes the SI worth getting right the first time.