3PL Onboarding Checklist: From Signing to First Ship

Onboarding a 3PL takes about a week for most brands. Whether it takes one week or six comes down almost entirely to how much of your own data is ready before day one — not to anything the warehouse does.

This is the checklist we work through with new brands, in the order it actually happens. If you are still deciding who to send it to, start with how to choose a 3PL instead, then come back here once you have picked one.

Before you sign: pull three files

Every onboarding delay we have seen traces back to one of these three things not existing yet. Get them together while you are still negotiating and the rest of the process stops being a bottleneck.

A SKU master. Every active SKU with its barcode, unit dimensions, unit weight, and case pack quantity. Not "roughly a pound" — the actual number, because it decides your shipping cost on every single order.
One full month of order history. Real orders, with destination ZIP codes and line counts. This is what lets a 3PL price your account honestly instead of quoting you a rate card.
Your inbound schedule for the next quarter. What is arriving, roughly when, and in what form — pallets, floor-loaded cartons, or a sea container.

Those same three files are what you should have sent to each candidate during the quote stage, so if you ran that process properly they already exist.

Connect the store before you ship the stock

The most common sequencing mistake is sending inventory first and sorting out the integration afterwards. Do it the other way around. Connect your store — Shopify, Amazon, TikTok Shop, WooCommerce, eBay, or one of the other 120+ platforms — and let orders flow into an empty warehouse for a few days before any product arrives.

Nothing ships yet, but you find out immediately whether SKUs are mapping correctly, whether tracking is writing back to your store, and whether your multi-channel inventory is reconciling the way you expect. Discovering a SKU mismatch on an empty floor costs you nothing. Discovering it with 40 orders waiting costs you a weekend.

Make your SKU data warehouse-ready

A picker works from a barcode, not from a product name. Three things are worth fixing before your first pallet ships:

Every unit needs a scannable barcode. If some of your products ship in unbranded polybags with no barcode, they will need labeling on arrival — which is billable work and adds days to receiving. Cheaper to have your supplier apply them.
Kill your duplicate and retired SKUs. Old variants that no longer sell still get received, shelved and stored. You pay rent on all of it.
Name variants so a human can tell them apart. "Blue-L" and "Blue-Large" as two live SKUs is a mis-pick waiting to happen, and no amount of warehouse process fixes an ambiguity you created upstream.

Time the first inbound so you don't pay twice

There is a window during a 3PL transition where you are paying for storage in two places. Keeping it short is worth real money.

Send a small first shipment — your top 10 to 20 SKUs by volume, enough for two or three weeks — rather than your entire catalogue. You validate the whole chain end to end on inventory that matters, and you are not moving slow-moving stock twice if something needs adjusting. Once the fast movers are shipping cleanly, send the long tail.

Ask for the receiving appointment in writing, and ask how long check-in takes once the truck is at the dock. Inventory that has arrived but is not yet checked in is not sellable, and that gap is where stockouts hide during a transition. Storage runs about $18 per pallet per month for standard space and around $32 for climate-managed, so a clear inbound plan also tells you what your first invoice should look like — our breakdown of Houston 3PL costs covers the rest of the line items.

If your stock is arriving in a container

Importers have an extra step, and it is the one most worth getting right. A container that clears customs and then sits on a chassis is costing you per-diem and detention every day, and none of that inventory is sellable while it waits.

If your 3PL can dray and devan the container themselves, tell them the vessel and arrival details as early as you have them so the dray can be scheduled against the actual free-time window rather than after it closes. The alternative — port to a trucker, trucker to a transload facility, transload to the warehouse — is three handoffs, three invoices and three chances for a day to disappear.

Agree the exceptions before they happen

Go-live is when everyone is being careful. The questions worth answering are about the ordinary Tuesday three months from now:

What happens when inbound arrives short or damaged — who counts it, who tells you, and how fast?
Who pays to reship a mis-picked order?
How does a carrier claim get filed, and by whom?
How do you get a rush order out after the daily cut-off?
Who specifically do you email, and what does a normal response time look like?

Write the answers down somewhere both sides can see them. Onboarding is the only moment when you have everyone's attention for this conversation.

What go-live actually means

Go-live is not a big-bang switch. It is a day where orders start routing to the new warehouse and you watch the first ones move.

Pick a Tuesday or Wednesday, never a Friday and never inside a promotion. Place two or three test orders yourself before you flip real volume — to your own address, one single-item, one multi-item, one to a far zone — and confirm the whole loop: order arrives, gets picked, ships, and the tracking number lands back in your store. Then let real orders through.

From that point the daily rhythm is simple: orders reaching us by 2 PM Central on a business day ship the same day, anything later goes out the next. Carriers are selected by cost and speed across USPS, UPS and FedEx, and from Houston ground service reaches roughly 60% of the US population in one to two days — so a meaningful share of your orders arrive in two days at ground prices.

The first two weeks after go-live

Watch three numbers, and watch them daily at first:

Cut-off compliance. Are orders placed before the cut-off actually shipping that day? If not, find out whether it is a warehouse issue or an integration lag pushing orders through late.
Inventory accuracy. Does the portal count match a physical spot-check on your top SKUs? Catch drift in week one, not during a stockout in month three.
Your first invoice, line by line. Against the priced month you were quoted. Ask about anything you do not recognise. An itemized bill is only useful if someone reads it.

Set a low-stock alert on your fast movers on day one rather than waiting until you need it. The point of a live inventory portal is that you see the problem before your customers do.

A realistic timeline

With your SKU data, order history and inbound schedule ready, most brands are shipping from Houston within a week: integration connected in the first day or two, first inbound received and shelved a few days later, test orders, then live. The week stretches when the SKU master has to be rebuilt from scratch or the first shipment turns up unannounced — both of which are within your control, which is the useful thing about this list.

If you want the specifics for your account before you commit to anything, send us that month of orders and your SKU list and we will come back within 24 hours with a costed month and a receiving plan. No setup fees and no long-term contract, so the decision stays reversible.