Moving a customer's fulfilment operation to a new third-party logistics provider is one of the highest-stakes projects a business can take on. For a window of several weeks, the thing the business depends on most is getting orders out the door, and during a migration that process is in motion with the usual safety nets gone.
Stock is being counted, recounted and physically relocated. Integrations are being re-pointed. Everyone, at every level, is making decisions faster than they normally would.
We've been through enough of these to know that the problems are rarely the ones you planned for. Here are ten things worth watching, and where possible getting ahead of, before they become expensive.
1. Know When to Push Back
A go-live is a delicate time and some choices carry outsized consequences. Under pressure, customers will sometimes ask for shortcuts: a last-minute config change, a skipped test, a "just do it now" that hasn't been thought through.
Part of our job is to be the voice of caution. If something looks risky, we say so. We're willing to say "not yet" or simply "no". The cost of a mistake during a 3PL migration is far higher than at any other point in the project, and "we didn't have time to check" isn't a sentence anyone wants to be saying afterwards.
2. Plan Your Stock Reconciliation Across Three Systems, Not Two
In any 3PL integration, the ERP holds the business's record of stock. Those figures need to be regularly reconciled against what the 3PL's system shows, and any discrepancies properly investigated, not carried forward and explained away each month.
When you're moving 3PLs, a third system enters the picture. For a period of time you have the ERP, the outgoing 3PL, and the incoming 3PL all holding figures that need to agree. The risk is the physical transfer itself. Stock leaving the old warehouse needs to be counted, confirmed, and properly received into the new one. If there's no formal handoff and reconciliation at that point, discrepancies get baked in from day one and you'll spend weeks afterwards trying to work out where they came from.
We make sure a reconciliation process is agreed and documented before any stock moves: what gets counted, when, by whom, and what happens if the figures don't tally on the other side.
3. Increase Lead Times in the Run-Up to the Move
During the transition, stock is in transit, being counted, or sitting in limbo between two sites. We always pad published lead times. It's far better to under-promise for a couple of weeks than to stack up SLA breaches and unhappy customers during the most fragile part of the project. Once the new site is running smoothly, we pull them back.
4. Work Out How to Bulk-Update Orders in Both Systems Before You Need To
There will be in-flight orders straddling the cutover. We need a way to move, close or re-point them in bulk in both the old and the new system, and a fair amount of that work will be manual.
We work out the method in advance. A script, a CSV import, a saved-search export. We test it before we're under pressure, because you won't have time to figure it out on the day.
5. Establish Who Is Responsible for What, and Get Mobile Numbers
Roles blur during a migration. "I thought you were doing that" is a recurring cause of go-live failures. Before the project enters its final stages, write down who owns each piece: stock counts, integrations, carrier setup, customer comms, returns.
Then get mobile numbers for the key people on every side. Go-live day moves fast, you need to be able to reach people directly, not wait on an email chain.
6. Run Daily Standups and Show Up to All of Them
A short daily standup keeps everyone aligned and surfaces problems while they're still cheap to fix. You should go even when a topic isn't directly relevant to your role. Context is worth more than it looks.
Something you pick up in passing about a carrier setup or a stock count often turns out to explain a baffling problem three days later. Knowing what's happening across the whole move is half the battle.
7. Review Every System That Touches the Warehouse, Not Just Shipping
A warehouse move isn't just about getting parcels out. Stock feeds to marketplaces, supplier reports, EDI, returns platforms, finance reporting: all of it can be affected, and the integrations you forget about are the ones that bite.
We build a list of everything that connects to the warehouse and work through it methodically, ticking each one off deliberately rather than trusting memory of what is and isn't connected.
8. Document What the Integration Does and Doesn't Do
Users will assume the integration handles things it doesn't, and will try to do things through it that will silently fail. We document the scope clearly: what flows, in which direction, and what falls outside it entirely.
We share it before go-live, not after the support tickets start coming in. Getting this out beforehand saves a week of confused back-and-forth once the project is live.
9. Push Complexity Into the ERP, Not Onto the Warehouse Floor
We aim for a fill-or-kill model. We keep all the logic inside the ERP: when orders release, dispatch dates, routing rules. That way the warehouse just ships what it receives, with no judgement calls required on the floor.
The less the warehouse has to decide for itself, the fewer errors we see. If you're running on NetSuite, the platform handles this well, so we use it.
10. Go On Site
Nothing beats being there. You'll understand the actual flow of goods, see where things snag, build relationships with the floor staff, and catch problems a screen will never show you.
Around go-live especially, be there. An hour walking the warehouse will teach you more than a week of calls and screenshots.
Putting It All Together
None of these are complicated on their own. What makes a 3PL migration hard is that they all land at once, under time pressure, with a business depending on you getting them right.
We plan for them early. We stay close to the people doing the work. And we're willing to slow things down when our gut says something isn't ready. A delayed go-live is an inconvenience. A broken one is a much bigger problem.
If you're planning a 3PL move and want to talk through the integration or systems side, particularly if you're running on NetSuite, get in touch with the team at Fowlers Consulting.