Last month I got to do something I’ve wanted to do for years. I went on a tour of LCY3, Amazon’s distribution centre in Dartford and the biggest one in Europe. After six years of helping brands sell on Amazon, I thought I had a pretty good picture of what happens when you send your stock into FBA. It turns out there was a lot I didn’t know, and some of it genuinely changes how I’ll be advising clients.
Just how big are we talking?
The building is over a mile long. Each of the 3 stow and pick floors is that size, and staff can move around on yellow bikes, because walking simply takes too long. I went in expecting big. I wasn’t expecting “some staff commute by bike within the building” big!
It’s far more manual than I expected
I’d built up a picture in my head of a fully automated warehouse with robots gliding around and barely a person in sight. That’s not what I saw. There are robots, and I’ll come to those, but what struck me most was how many people are involved, and how many different jobs there are. Boxes get taken off the lorry, opened, scanned and checked by hand, before being placed in a large plastic box called a tote to be taken upstairs (via conveyor belt) to the stow and pick floors.
Your packaging doesn’t go to waste
One detail I loved. The boxes and packaging sellers use to send stock in for FBA get recycled, and turned into Amazon’s own packaging materials. So there’s a decent chance the cardboard envelope your last Amazon order arrived in started life as a seller’s shipment box.
Your stock isn’t stored together – and there’s a good reason why
This was the bit that surprised me most and I think will surprise a lot of sellers too. I’d assumed that if you sent in a hundred units of your product, they’d sit together on a shelf somewhere. They don’t. There aren’t even shelves in the way you’d picture.
Instead, items go into pods (that’s the actual term Amazon uses), which are large storage units with cubbyholes of different sizes on every side. Robots called Hercules bring these pods to staff at stow and pick stations. And your stock gets deliberately spread across lots of different pods, wherever there’s space, rather than kept together.
The reason goes back to Harry Potter and the Deathly Hallows, the final book in the series, which set Amazon’s biggest ever pre-order record at the time. Apparently when a huge release like that gets stored in one place, it creates a serious bottleneck. If one pod holds every copy of a bestseller, only the one picker working that pod can pick it, and everyone else is stuck waiting. Spread across many pods, any picker can reach it, and there’s no queuing at one part of the warehouse. So now, everything gets scattered on purpose, and it’s apparently far more efficient as a result.
How picking and packing actually works
When an order comes in, a picker isn’t picking your order specifically. They’re picking lots of different products for lots of different orders at once. The pod carrying the item they need gets brought to them by a robot, and the exact section lights up to show them where to look. They scan it, and it goes into a tote for the next stage.
For single item orders, here’s the bit I think that matters most for sellers. The packer’s screen tells them exactly what packaging to use, and that’s driven entirely by the dimensions you’ve entered in Seller Central. If those are wrong, even by mistake, your product can end up in a box that’s far too big for it. The packer can override this, but often won’t as it adds time they just don’t have.
Weight works the same way, and matters just as much. Every box gets weighed before it leaves the building, and Amazon checks that against what your listing says the contents should weigh. If it doesn’t match, the whole box gets pulled off the line and checked by hand. So if your weights and dimensions in Seller Central aren’t accurate, you’re not just risking an oddly sized box turning up at someone’s door. You’re adding delays and manual checks into a process that’s designed to run without them. It’s a genuinely worthwhile five minutes to go and check your listings.
For orders with multiple items, staff place each item into a cubby hole assigned to that order as it comes through on the conveyor belt. Once everything for that order is there, it gets pushed through to someone who packs it all into one box.
A nice privacy detail
Amazon staff don’t have access to customer data, and don’t know who’s ordered what. Every box first gets a small barcode label that only a machine can read, and that’s what identifies the order. Your name and address only get printed and applied once everything is securely packed. So right up until the very last stage, nobody handling your order actually knows who it’s for.
Damaged stock and returns
Things do fall off the conveyor belt – I saw it happen. When it does, the whole order gets picked again from scratch, and whatever fell gets assessed by a separate team to decide if it can go back into circulation. If you’ve ever had FBA stock flagged as damaged at the distribution centre, this is likely what’s behind it.
And distribution centres don’t handle returns at all. Every Amazon return goes to dedicated return centres, based in Scotland.
Final thoughts
After working on Amazon for such a long time, I didn’t expect to come away from a warehouse tour having learned quite this much. If there’s one practical thing to take from it, it’s this – the accuracy of your weights and dimensions in Seller Central isn’t a small admin detail. It genuinely affects what happens to your stock, and it’s worth checking properly rather than assuming it’s fine.