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How to Announce Inbound Stock to Your Prep Centre (ASN Guide)

An ASN — Advanced Shipping Notice — is simply telling your warehouse what's coming before it arrives: which SKUs, how many, from which supplier, on what vehicle, roughly when. It takes five minutes to file and it is the single highest-leverage habit in your relationship with a prep centre. Announced stock gets booked in fast, counted against a known expectation, and flagged immediately if something is short or damaged. Unannounced stock sits on the goods-in bay while somebody works out whose it is. Here's what a good ASN contains and how to make the process automatic.

Why warehouses care so much about ASNs

From the outside, "just receive the boxes" sounds trivial. From the inside, a goods-in bay on a busy morning holds deliveries for dozens of clients, from suppliers who label cartons in every conceivable way, including not at all. An ASN turns detective work into a checklist:

  • Identification. The team matches the delivery to your announcement instead of opening cartons to guess whose stock it is.
  • Verification. Counting against an expected quantity is how discrepancies get caught. Without an expectation, a supplier shorting you 40 units just becomes your inventory number.
  • Scheduling. Container deliveries especially — a 40ft arriving unannounced can't be devanned promptly because labour wasn't booked for it.
  • Speed. Announced deliveries jump the queue because the paperwork already exists. This is what makes 24-hour prep turnarounds possible.
  • Billing accuracy. Received quantities flow straight into your inventory and your invoice, tied to a reference you recognise.

Many warehouses charge surcharges for unannounced deliveries. Even where they don't, you pay in delay.

What to include in an ASN

| Field | Why it matters | | --- | --- | | Your reference / PO number | Ties the delivery to your records and the supplier's | | SKUs and quantity per SKU | The expectation everything is counted against | | Carton count and pallet count | First-glance check before anything is opened | | Supplier name | Cartons are often labelled with the supplier's name, not yours | | Carrier and tracking / container number | Lets the warehouse spot the vehicle and chase delays | | Expected arrival date (or window) | Labour planning, especially for containers | | Packaging notes | "Mixed cartons", "no barcodes on units", "fragile — glass" | | What to do next | Prep for FBA immediately? Hold in storage? Await instruction? |

The last two rows are where experienced sellers separate themselves. "Mixed SKU cartons" declared upfront is a routine job; discovered halfway through receiving, it stops the line. And a clear disposition — prep 300 for FBA shipment X, hold the rest — means stock moves the day it lands instead of waiting for an email exchange.

Announcing supplier and factory shipments

Most inbound stock comes from a supplier, not from you, which adds a wrinkle: you may not know exact carton counts until the supplier ships. The workflow that works:

  1. Create the ASN when you place the PO, with expected quantities and a rough window.
  2. Update it when the supplier confirms dispatch — actual cartons, tracking or container number, ETA.
  3. Tell your supplier to label cartons with your name or reference and a carton number ("3 of 12"). This one instruction to your factory eliminates most receiving confusion.
  4. For containers, share the container number and shipping line as soon as you have them so devanning labour can be booked for the delivery day.

What happens when the delivery doesn't match

The point of announcing isn't the happy path — it's the mismatch. A good prep centre's process when reality diverges from the ASN:

  • Count the discrepancy twice, then record it against the ASN line.
  • Photograph the evidence: short cartons, crushed boxes, water damage, wrong product. Photos taken at receiving are your ammunition for supplier claims and freight insurance — a week later they're worthless.
  • Notify you before doing anything irreversible, with the photos attached.
  • Quarantine damaged units rather than mixing them into sellable stock.

If a prospective 3PL can't describe this process, or receives stock without confirming counts back to you, that's a real warning sign: their inventory numbers are aspirational.

Common ASN mistakes

  • Announcing after the truck has left the supplier. Better than nothing, but you lose the scheduling benefit. Announce at PO time and update.
  • One ASN for multiple deliveries. If the supplier splits the shipment, file it as separate expected deliveries or amend the ASN — otherwise the first arrival "completes" the announcement and the second confuses everyone.
  • Round-number guessing. "About 1,000 units" defeats the purpose. Use the PO quantity; that's the number worth checking against.
  • No disposition. Stock that arrives without instructions defaults to storage — which is fine, unless you were expecting it at Amazon that week.

How Oakmont handles it

ASNs at Oakmont are filed in the client portal: SKUs, quantities, carton and pallet counts, carrier or container details, and disposition instructions, created in a couple of minutes and editable until the goods land. Everything is received against the announcement, discrepancies are photographed and posted to the ASN record so you see exactly what we saw, and received stock flows straight into your live inventory view. Announced FBA stock goes into our 24-hour prep turnaround; containers announced with a delivery date get devanning labour booked in advance (£250 for a 20ft, £375 for a 40ft).