Switching 3PL Providers: A Step-by-Step Checklist

TL;DR

Most switches take 60 to 90 days from signed agreement to stable operation. Your notice period with the current provider can be up to 90 days, so check your contract before you set a date. The risk concentrates into the few days when stock moves. This checklist walks through six phases (eight steps): notice and exit terms, selection, integration and data, stock transfer, parallel running and go-live, and post-switch review. It also covers when staying put is the better call, and why switching between September and December rarely makes sense.

Key Takeaways

A switch succeeds or fails on planning more than on the new provider, and the points below summarise what matters most.

• Most switches take 60 to 90 days from signed agreement to stable operation, and your current contract's notice period, often 30 to 90 days, sets the anchor
• A notice period that expires in October means moving stock in the worst month of the year, so time the decision around peak
• SKU and barcode mapping between the old and new systems is where most switches go wrong, so test it before any stock moves
• Every switch costs more than the quote once staff time, a dead period, discrepancy write-offs and a temporary accuracy dip are counted
• If the real problem sits in your own forecasting or product data, a new provider will inherit it

Read the section on whether to switch at all before starting phase one.

Switching 3PL Providers Step by Step

Changing 3PL providers is one of the biggest operational decisions an eCommerce brand makes, and most of the risk sits in the move itself. Months of planning lead up to the moment stock leaves one warehouse and arrives at another, and any mistake in that window shows up as missed orders, oversells or unhappy customers. A good plan shrinks that window and catches problems before they reach buyers. This guide is for eCommerce brands thinking about leaving their current 3PL, or already decided, who want a sequenced checklist from the first conversation to the first 90 days live.

The guide assumes you already use a 3PL and understand what third party logistics involves. It covers the switching process itself: notice and exit terms, choosing the new provider, rebuilding integrations and data, moving stock, running both sites, going live and reviewing the result. Separate Gonini guides cover accuracy measurement and the contract terms worth negotiating with your next provider.

Before going further, a clear disclosure. Gonini is a 3PL and benefits directly when brands switch providers, and this guide tells you how to do exactly that. To balance that interest, the next sections set out when staying with your current provider makes more sense, treat the costs of switching honestly, and admit that some brands are themselves the cause of the problems they want to escape. Without those points, this guide would be a sales funnel.

Durations and costs below come from published industry guides, checked on 15 October 2026, or from an illustrative example with every assumption stated. The methodology section sets out the brand profile behind those figures, since a 200-SKU brand and a 5,000-SKU brand face very different switches.

Quick Summary: The Switch at a Glance

A switch runs through six phases (eight steps), some of which overlap. The table shows a usual duration for each phase, who owns it and the main way it fails. Durations assume the brand profile in our methodology and are indicative.

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Contracting and integration often overlap with the notice period, which is why the whole switch can fit inside 60 to 90 days. Stock transfer and parallel running carry most of the operational risk, so they get the most detail below. The post-switch review is the phase most brands skip, and it decides whether the move actually solved the problem.

Methodology and Assumptions

The timings and costs in this guide assume a UK brand shipping around 3,000 orders a month from about 300 active SKUs, with roughly 12 pallets of stock and sales through its own website plus one marketplace. The move runs from one UK warehouse to another, with no international sites involved. A brand with ten times the SKUs, several marketplaces or stock across countries should expect longer timelines at every stage.

Most switches take 60 to 90 days from signed agreement to stable operation, covering integrations, stock transfer, testing and stabilisation. fulfilment.com, a UK marketplace that matches brands with 3PLs, reports onboarding times of 5 to 14 days at tech-first providers, 30 to 60 days at mid-market 3PLs and 60 to 90 days or more at enterprise providers. WareMatch, a 3PL marketplace, notes that 3PL contracts commonly require 30 to 90 days' written notice.

Costs come from EightX's UK 3PL cost index where available and from illustrative assumptions where not, and the worked example labels each one. Any provider you speak to should be able to share its own onboarding timelines for brands like yours, and that data will beat any published range.

Should You Actually Switch?

Staying with your current provider is a legitimate outcome, and often the cheaper one. Many fulfillment problems can be fixed with the incumbent through escalation, a remediation plan and clearer commitments. Before you give notice, test whether the problem is fixable where you are.

Start with evidence. Gather error rates, despatch performance and stock accuracy over several months, using consistent definitions, and compare them with what your contract promises. Gonini's guides to order accuracy and fulfillment SLAs cover how to build that case and what a reasonable remediation period looks like.

Some problems point clearly towards leaving: a provider that cannot handle your product type, cannot support a channel you need, has repeatedly failed remediation plans, or is moving in a direction that no longer fits your business. Others point towards fixing things where you are, such as a single bad peak, a staffing gap the provider is already addressing, or a pricing dispute that negotiation could solve.

Check your own side as well. If stockouts come from your own forecasts, errors trace back to inaccurate product data, or your team sends stock without notice, a new provider will inherit the same problems. The uncomfortable pattern in this market is that some brands switch repeatedly, and the common factor is the brand rather than the providers.

Phase One: Notice and Exit Terms

Phase one sets the timeline for everything else, because your current contract decides how soon you can leave and on what terms. Read it before you speak seriously to any new provider. The three sections below cover what to look for.

Reading Your Contract Properly

Start with the termination clause, notice period, minimum term and any auto-renewal date. Some contracts renew automatically for another year unless you give notice by a set date, which can trap a brand that leaves the decision too late. Note every date on a single timeline.

Look for conditions on how stock leaves. WareMatch notes that some contracts include obligations on how inventory must be packaged or palletised before it can be released, which adds cost and time at the end. Check also whether the provider can hold stock against unpaid invoices, and how it handles data exports when the relationship ends.

Notice Periods and the Peak-Season Trap

Notice periods of 30 to 90 days are common, and they interact badly with peak. A brand that gives three months' notice in July will find its notice expiring in October, which means moving stock in the worst possible month, just as volumes climb towards Black Friday. Count backwards from your target go-live date rather than forwards from the day you decide.

Starting a switch in early September leaves only about eight to ten weeks before volumes climb in November. If the timing does not work, document the problems now and plan the move for the new year.

Exit Fees, Final Invoices and Stock Release

Exit costs vary. Some contracts charge an early termination fee or require payment for the remaining minimum term, while others simply charge for handling stock out. Ask your current provider for a written statement of all exit charges before you give notice.

Agree how the final invoice works and when stock will be released. Disputes over final invoices are a common cause of delayed stock release, so settle open queries early and keep payments current during the notice period. A cooperative exit is far easier than a contested one.

Phase Two: Selecting the New Provider

Selection deserves its own process, and this guide keeps it brief. Our guide to the full selection checklist covers how to shortlist and compare providers, including site visits and references. The aim here is to fit selection into the switching timeline without rushing it.

Ask every shortlisted provider how it handles inbound transfers from another 3PL, how long its onboarding takes for brands like yours, and who will run your onboarding day-to-day. Our list of questions to put to a new provider covers the wider set. Ask to speak to a brand that switched to them within the last year.

Check that the provider's model suits you. Some providers suit high-volume, simple products, while others handle complex kitting, B2B orders or fragile goods, and our overview of the main fulfillment models explains the differences. A provider that fits your product profile will usually cause fewer problems in transition than a cheaper one that does not.

Phase Three: Integration and Data

Integration and data work decides whether the new provider can receive your orders and ship the right items. fulfilment.com estimates that connecting your storefront, ERP and the provider's warehouse system takes 60% to 70% of total onboarding time at mid-market providers. Most of that time goes into making products, orders and stock levels match across systems.

The new provider's warehouse management system needs to connect to your sales channels, receive your product data and return stock levels and tracking. The three sections below cover channel integrations, product data and the orders already in flight.

Rebuilding Channel Integrations

Each sales channel needs reconnecting to the new provider, along with any order management or inventory tools in between. Standard app connections can be quick, while custom integrations take longer. Marketplaces with their own fulfillment rules may need extra testing.

Stock sync matters most. While both providers hold stock, your channels need to read stock levels from the right place, and errors here cause oversells. Our guide to stock sync across channels covers how stock levels flow between systems.

Test with real orders before go-live. Place test orders through every channel, check that they reach the new provider correctly, and confirm that tracking flows back to the customer. Fix every failure before any live order depends on the connection.

SKU Data, Barcodes and the Mapping Problem

The mapping problem is where switches actually go wrong. Your products carry identifiers in several places: your store's SKU codes, marketplace listing IDs, manufacturer barcodes and the old provider's internal codes. The new provider needs a clean map between all of them, and any mismatch sends the wrong item or blocks an order.

Common faults include two variants sharing a barcode, barcodes missing from some products, SKU codes that changed over time, bundles set up differently in the old system, and products the old provider labelled with its own internal barcodes. That last one catches many brands, since stock carrying the old provider's labels may not scan at the new site.

Audit product data before anything moves. Export the full product list from every channel and from the old provider, match them line by line, and resolve every gap. Products with no reliable barcode may need labelling, and our guide to barcodes and SKU identification explains what the new provider will need.

Order History, Returns in Flight and Open Orders

Orders do not stop for a switch. On cutover day, some orders will be picked but not shipped at the old site, some will be in transit, and some customers will be about to send returns. Agree which provider handles each group and for how long.

Returns cause the most confusion. Customers who received orders from the old site will send returns to the address on their paperwork, so update returns addresses on your website and labels well before cutover, and agree how the old provider forwards stragglers. Our guide to returns handling covers the wider process.

Export order history from the old provider before access ends. Order records, tracking numbers and returns data help with customer service queries for months afterwards, and some providers close portal access soon after a contract ends.

Phase Four: Moving the Stock

Moving stock is the moment of greatest risk, since stock in transit cannot be sold. The goal is to move it accurately and quickly, with as short a gap as possible. The three sections below cover methods and costs, reconciliation, and the dead period.

Transfer Methods and What Each Costs

There are three common approaches. A single move transfers everything at once, which is simple and creates the longest gap. A phased move sends enough stock to cover sales at the new site first, then moves the rest. A run-down approach keeps the old site selling until its stock runs out, while new deliveries go straight to the new site.

You do not have to move all your stock at one time. When one brand moved to us from a large 3PL, we moved half of its stock first and kept the rest at the old warehouse. Our team set up the brand's Shopify store to send orders to both warehouses at the same time. Orders at our warehouse grew while the stock at the old warehouse ran down. The brand stayed online through the whole move, and it avoided a large fee for removing all its stock at once, which can be expensive. Our onboarding team plans a different approach for each brand.

Costs come from freight, handling and goods-in. Pallet freight quotes depend on pallet size, weight, distance and postcodes, so get quotes for your own route. EightX, a finance consultancy for eCommerce brands, puts handling at around £1.30 to £3.50 per pallet in and out in its UK 3PL cost index, and receiving at around £1.50 per SKU plus a fraction of a penny per unit.

The example below estimates a single-move transfer for the brand profile in our methodology. Every figure is illustrative unless sourced above, so replace each one with your own quotes.

• Freight: 12 pallets at £45 each, allowing for distance and full-size pallets, gives £540
• Release handling at the old provider: 12 pallets at £3 each gives £36
• Goods-in at the new provider: 300 SKUs at £1.50 plus 30,000 units at £0.005 gives £600
• Overlap storage: 12 pallets held at both sites for four weeks at £4 per pallet per week gives £192 extra
• Internal staff time: 40 hours at £25 per hour gives £1,000
• Discrepancy write-off: 0.5% of £60,000 stock value gives £300
• Total: about £2,668, before any exit fee or sales lost during the dead period

The goods-in assumption uses the EightX receiving rate, with £0.005 per unit as an illustrative per-unit charge. Internal staff time and write-offs rarely appear in quotes, and yet together they make up nearly half of this estimate, which is why switches usually cost more than the provider's quote.

Counting, Reconciling and Resolving Discrepancies

Count stock before it leaves and when it arrives. The old provider should produce a final stock report and pack stock by SKU with clear labelling, while the new provider should count every unit on receipt and report against that list. WareMatch advises reconciling received stock against your documented count as soon as it arrives, and keeping packing lists, photos of inbound cartons and receiving confirmations as a paper trail.

Discrepancies are normal, and the real question is who absorbs them. Agree in advance how differences get investigated, what evidence each side provides, and which differences count as the old provider's loss. Small discrepancies often trace to mislabelled cartons or units split across pallets, so a recount often resolves them.

Use your own records as a third reference. Your sales data and purchase orders show what stock you should have, which helps when the two providers' figures disagree. Resolve discrepancies quickly, since memories and paper trails fade.

The Dead Period, and How to Shrink It

The dead period is the time when stock sits in transit or at goods-in and cannot be sold. With a single move, it can last several days, and longer if goods-in falls behind. Every day of dead period means lost sales or delayed orders.

Several tactics shrink it. Leaving a small working stock of bestsellers at the outgoing provider covers orders during the transfer window, and you can run it down once the new site is live. Book the new provider's goods-in capacity in advance so stock gets counted and put away fast, and move slow sellers first and fast sellers last.

Plan for things going wrong. A delayed lorry, a receiving backlog or a large discrepancy can stretch the dead period, so prepare customer messaging, consider pausing paid ads on affected products, and agree a fallback. Our guide to contingency planning covers how to plan for disruption more generally.

Phase Five: Parallel Running and Go Live

Phase five moves orders from the old provider to the new one. Some brands run both sites at once for a period, while others cut over on a single day. The sections below cover whether parallel running is worth it, how to sequence the cutover, and what to watch in the first week.

Running Both Sites at Once, and Whether It Is Worth It

Parallel running means both providers ship orders for a period, with stock split between them. It lets the new site prove itself before the old one closes. It also gives you a fallback if the new site struggles.

Parallel running costs more and adds complexity. You pay storage and fees at both sites, your stock sync has to route orders to whichever site holds stock, and oversells become more likely if the split goes wrong. For a small brand with simple products, a well-planned single cutover can be cheaper and safer.

A middle path is a pilot. Piloting a handful of SKUs tests integrations and processes without splitting your whole range.

Cutover Sequencing

Cutover is the moment new orders start routing to the new provider. Choose a quiet day, usually midweek and well away from promotions, and agree the exact time orders switch. Freeze product and pricing changes for a few days either side, so nothing else changes while the routing does.

Sequence the steps in writing. Confirm stock is live at the new site, switch order routing, check the first orders reach the new provider, confirm the old provider has shipped its remaining orders, then switch returns and stock sync. Name an owner for each step and a time by which it should finish.

The First Week and What to Watch

The first week shows whether the switch worked. Check that every order flows through, despatch meets the agreed cut-off, stock levels match across systems, and customer contacts stay at normal levels. Daily calls with a named onboarding contact at the new provider help resolve problems fast.

Expect some disruption. Plan for a few weeks of closer oversight after go-live, since accuracy often dips while the new team learns your products. Track issues in one shared log so patterns show quickly.

Phase Six: Post-Switch Review

The post-switch review checks whether the move solved the problem that started it. Without a review, brands often accept a temporary dip as the new normal, or miss early signs that the new provider has its own issues. Schedule reviews at 30, 60 and 90 days, and agree them before go-live.

Measure the same things you measured before the switch, using the same definitions, so you can compare like with like. Our guide to the metrics to track afterwards covers the full set, and the list below sets out what each review should cover.

• 30 days: order accuracy, despatch against cut-off, stock accuracy after the first cycle counts, and any open discrepancies from the transfer
• 60 days: trends in each measure, customer contact volumes, returns processing times and invoice accuracy against the quote
• 90 days: performance against the original reasons for switching, total switching cost against budget, and any changes needed to processes or SLAs

Delivery performance belongs in the review too, since a new site may change carrier options and transit times. Measures such as on time in full as a measure show whether customers receive orders when promised. If results at 90 days fall short of the reasons you switched, raise it early, while the new relationship is still flexible.

What Switching Costs and What It Cannot Fix

Switching always costs more than the quote. Staff time, the dead period, discrepancy write-offs, overlap storage and a temporary accuracy dip while the new team learns your stock rarely appear in a provider's proposal. The worked example above shows how quickly those items add up even for a modest brand.

It is rarely worth switching between September and December. Moving stock during the run-up to peak adds risk exactly when errors cost most, and new providers have less capacity to give your onboarding proper attention. If your current provider is failing badly, fix what you can for peak and plan the move for the new year.

Peak season does not rule a move out, though. A small UK food brand moved to us from another 3PL at Christmas. You can change warehouse during peak, but plan for the move to take a little longer than it would in a quieter month.

A switch also cannot fix problems that start with the brand. Poor forecasting, inaccurate product data, late purchase orders and unannounced deliveries will cause the same problems at any provider. Fix those first, or the new relationship will repeat the old one.

Finally, some brands switch repeatedly and run into the same frustrations each time. If you are on your third provider in as many years, look at what the three experiences have in common before signing a fourth. A frank, evidence-based conversation with your current provider may solve more than another move.

FAQ

How long does it take to switch 3PL providers?

Most switches take 60 to 90 days from signed agreement to stable operation. Your notice period can be up to 90 days. See how we handle switching 3PL.

What does it cost to move stock to a new 3PL?

Freight, handling, goods-in, overlap storage and staff time. See the components of a fulfillment bill for each line.

Will I have downtime when changing fulfillment provider?

Usually a few days of reduced availability, unless you keep bestseller stock at the old site or run both sites at once. See our guide to stock sync across channels.

When is the worst time to switch providers?

September to December, in the run-up to peak. Read our peak season planning guide before setting a date.

What happens to orders already in progress?

The old provider ships orders it already holds. Agree who handles open orders, returns and late arrivals before cutover. See our guide to returns handling.

How do I handle stock discrepancies during a transfer?

Count before and after, investigate differences quickly, and agree who absorbs losses. See stock audits and counts.

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