The IMD Guide
Third-party logistics (3PL): a complete guide
What a 3PL actually does, how the model works, what it costs, and how to choose the right partner — written for growing UK ecommerce brands weighing up whether to outsource.
JQ
Jake Quenet
11 min read · Updated June 2026
"3PL" gets used constantly in ecommerce circles, often without anyone stopping to explain it. If you've reached the point where packing orders is eating the time you should be spending on growth, it's a term worth understanding properly — because handing your logistics to a third party is one of the biggest operational decisions a growing brand makes.
This guide explains what a third-party logistics provider is, where it sits among the other "PLs" you'll see thrown around, exactly what a good 3PL handles on your behalf, how the pricing really works, and the questions worth asking before you sign with anyone. It's written for UK brands, so the carrier, customs and compliance details reflect how things actually work here.
01 — WHAT IS A 3PL?
Start with the basics
What is a 3PL?
A third-party logistics provider — a 3PL — is an outsourced partner that runs your fulfilment operation for you. You send them your stock; they store it, pick and pack each order as it comes in, ship it to your customer, and handle returns when they come back. Instead of running your own warehouse, hiring your own pickers and negotiating your own courier contracts, you plug into infrastructure that already exists.
The "third party" simply means a business outside the buyer-seller relationship. You sell the product, your customer buys it, and the 3PL is the third party that moves it between you. Done well, the customer never knows a 3PL was involved at all — the parcel arrives quickly, accurately and on brand.
For most growing ecommerce businesses, a 3PL is the bridge between "running fulfilment from the spare room" and "operating like an established brand" — without the capital, the lease, or the headcount that building it yourself would demand.
02 — THE LOGISTICS LADDER
1PL, 2PL, 3PL, 4PL — what the numbers mean
The "PL" scale describes how much of your logistics you've handed over. Knowing where each rung sits makes it much easier to work out what you actually need.
1PL — First-party logistics
You do everything yourself. You hold the stock, pick the orders, and drop them at the Post Office. Every early-stage brand starts here. It works until volume outgrows it.
2PL — Second-party logistics
An asset-owning carrier that physically moves goods — a courier, a haulier, a freight line. Royal Mail collecting your parcels is a 2PL relationship. They transport, but they don't manage your wider operation.
3PL — Third-party logistics
The full operational layer: storage, inventory management, picking, packing, dispatch, returns and the carrier relationships that sit underneath. A 3PL doesn't just move parcels, it runs the warehouse and the order flow on your behalf. This is where most eCommerce brands land.
4PL — Fourth-party logistics
A strategic, "control-tower" layer that manages your entire supply chain, often coordinating several 3PLs and carriers at once. Usually non-asset-based — they orchestrate rather than operate. Larger, more complex businesses tend to need this.
5PL — Fifth-party logistics
A newer, data-led tier that designs and manages whole logistics networks, typically for marketplaces or businesses running at serious scale. Most brands will never need to think about it.
For the overwhelming majority of growing UK ecommerce brands, the right answer is a 3PL. It's the rung that removes the operational burden without taking strategic control out of your hands.
03 — WHAT A 3PL DOES
The work a good 3PL takes off your plate
"Outsourcing fulfilment" sounds simple until you list everything it covers. A capable 3PL handles all of this as one joined-up operation:
Receiving (goods-in)
Inbound stock is booked in, checked against your purchase order, and logged into the system so every unit is tracked from the moment it lands.
Warehousing and storage
Stock is stored in a clean, secure, organised environment, laid out so picking stays fast and accurate — and so you only pay for the space you actually use.
Inventory management
Live visibility of every SKU: what's on the shelf, what's allocated to open orders, what's been dispatched, what's come back. Good inventory data is what stops you overselling.
Pick & pack
The live stage — the moment an order lands, items are picked, scan-verified for accuracy, and packed to your specification, whether that's plain, branded, or with custom inserts.
Shipping and carrier management
The 3PL rate-shops across multiple couriers, generates the label, and gets the parcel collected — using volume-negotiated rates most individual brands can't access.
Returns
Parcels come back, are assessed and processed on receipt, and your live stock count updates automatically.
Value-added services
Many 3PLs also handle kitting, bundling, subscription-box assembly, branded packaging and marketplace prep — the finishing touches that make the unboxing feel like yours.
Estimate it for your operation
The thread running through all of it is integration: a good 3PL connects directly to your sales channels so orders flow in automatically, with no manual exports and no copy-pasting between systems. Check out what it could cost you to work with a 3PL:
Estimates are based on UK industry averages for pallet storage (£3–£6 per pallet per week) and pick & pack (£1.50–£3 per order). Final pricing depends on your SKUs, order profile and service level — get in touch for a tailored quote.
04 — Types of 3PL
Not all 3PLs are built the same
The label covers a wide spread of businesses. Broadly, you'll come across a few distinct types.
By what they own
Asset-based 3PLs own their warehouses, equipment and sometimes vehicles. Non-asset-based 3PLs coordinate logistics using other companies' infrastructure. Asset-based providers tend to offer more direct control and consistency over the operation.
By specialism
Some 3PLs are transportation-led (their strength is shipping and carrier relationships), some are warehouse- and distribution-led (storage, picking and packing are the core), and some are freight-forwarding-led (built around international movement and customs). The right fit depends on where your bottleneck actually is.
By market
This is the big one for online brands. A general or B2B logistics 3PL is built for pallets, bulk and retail distribution. An ecommerce-specialist 3PL is built for direct-to-consumer order profiles — high volumes of small, individual parcels, tight dispatch cut-offs, real-time channel integrations and customer-facing delivery experiences. If you sell D2C, an ecommerce-native 3PL will almost always serve you better than a traditional logistics firm.
By sector
Some 3PLs specialise further — cold-chain for food and drink, compliant handling for supplements and cosmetics, secure storage for high-value goods, or category expertise in areas like fashion. If your products carry specific requirements, a specialist matters.
05 — HOW A 3PL WORKS
What actually happens once you're set up
The day-to-day is more straightforward than it sounds. Once you're onboarded, the operation runs on a loop:
You ship stock to the 3PL
It's received, checked and booked into the warehouse system.
Your sales channels are integrated
Shopify, WooCommerce, Amazon, TikTok Shop and the rest feed orders straight to the warehouse the moment a customer checks out.
Orders are picked and packed
Each one is barcode-verified for accuracy and packed to your spec.
Parcels ship
The system picks the right courier, the label is generated, tracking goes live, typically same-day if the order came in before the dispatch cut-off.
Returns are processed
Anything coming back is scanned in, assessed and restocked, with stock levels updating in real time.
Sitting over the top of all of it is the software. A good 3PL gives you a real-time view of orders, stock and returns from anywhere, so fulfilment becomes something you can see and measure rather than something you hope is going to plan.
06 — IN-HOUSE VS 3PL
Running it yourself vs handing it over
Doing fulfilment in-house gives you total control over every detail — but that control comes at a cost. You're investing capital in space, staff and systems; you carry all the overhead on your P&L; and capacity is hard to flex when orders spike or dip. Peak season either leaves you scrambling for temporary staff or paying for space you don't use the rest of the year.
A 3PL flips the model. You plug into infrastructure and courier rates that already exist, pay only for the capacity you actually use, and scale naturally with volume. The trade-off is that you're trusting specialists to run the day-to-day rather than overseeing it yourself — which is exactly why choosing the right partner matters so much.
For most growing brands, the crossover point arrives sooner than expected: usually the moment packing orders starts eating the hours you should be spending on product, marketing and growth.
07 — 3PL VS 4PL
When you need orchestration, not just operation
The simplest way to separate the two: a 3PL operates your logistics, while a 4PL orchestrates it. A 3PL runs the warehousing, picking, packing and shipping. A 4PL sits a level above, managing your whole supply chain — often coordinating multiple 3PLs, carriers and suppliers through a single point of contact.
For a single-warehouse ecommerce brand, a 3PL is almost always the right answer. A 4PL starts to make sense when you're running complex, multi-region supply chains with several logistics partners that need a strategic layer tying them together. Most brands grow into a 3PL long before they ever need a 4PL — and many never need one at all.
08 — WHAT IT COSTS
How 3PL pricing actually works
Pricing
A 3PL rarely charges a single flat per-order rate. Pricing is usually spread across five lines, and comparing just one of them in isolation is the fastest way to pick the wrong partner.
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Receiving fees — for booking in and processing inbound stock, usually per pallet or per carton.
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Storage fees — charged per pallet, shelf or cubic metre, weekly or monthly. Often the biggest fixed line on the bill.
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Pick & pack fees — per order, sometimes with a small per-item charge for multi-line orders. Scales directly with sales.
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Shipping costs — either passed through at the 3PL's negotiated rate or built into the per-order price. Volume buys leverage.
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Returns handling — a per-return fee covering inspection, restocking and handling.
As a rough UK benchmark, pallet storage tends to run around £3–£6 per pallet per week and pick & pack around £1.50–£3 per order — but your real number depends on your product types, order profile and service level. Some providers publish standard rate cards; others (IMD included) build bespoke pricing around your actual volumes rather than squeezing you into a one-size-fits-all package. When you're comparing quotes, look at the total cost per order, not individual line items — the balance between the five lines varies a lot between providers.
09 — CHOOSING A PARTNER
What actually matters when comparing 3PLs
The cheapest per-order rate rarely tells the full story. When you're weighing up providers, these are the questions worth asking every one:
Questions worth asking any 3PL
What's your pick accuracy, and is it barcode-verified?
What's your same-day dispatch cut-off?
How do you price — and what isn't included?
Which sales channels do you integrate with, and how quickly?
What real-time visibility do I get?
How fast can you onboard me, and what happens at peak?
A good answer to all six points to a partner you can grow with. Vague answers to any of them are worth taking seriously.
10 — 3PL FOR UK ECOMMERCE
The UK-specific details that matter
If you're a UK brand, a few things are worth checking beyond the basics. A good UK 3PL doesn't lean on a single carrier — it rate-shops across Royal Mail, Evri, DPD, Parcelforce, DHL and FedEx to balance speed, cost and coverage on every order, and handles the coverage quirks (Highlands & Islands, Northern Ireland, the Channel Islands) without leaving you to discover surcharges at checkout.
It should also keep you compliant. If you're an overseas brand storing stock in the UK, your fulfilment partner needs to be registered with HMRC under the Fulfilment House Due Diligence Scheme (FHDDS). And once you start shipping into the EU or further afield, the customs documentation, VAT treatment and DDP/DAP decisions become part of the operation — the right partner handles most of that paperwork for you.
For a fuller walkthrough of carriers, international shipping and UK regulation, our ecommerce fulfilment guide goes deeper — this guide focuses on the 3PL model itself.
BY THE NUMBERS
What you can expect from IMD Fulfilment
99.98%
Pick accuracy across every order, barcode-verified.
3pm
Same-day dispatch cut-off — orders in by 3pm go out today.
2
UK distribution hubs giving you resilience and capacity.
2003
Year founded — two decades of ecommerce fulfilment experience.
11 — FAQ's
Everything else you might be wondering
The practical questions ecommerce brands ask before signing on with a 3PL — grouped by theme.
What does 3PL stand for?
What's the difference between a 3PL and a fulfilment centre?
Is a 3PL the same as a courier?
How much does a 3PL cost in the UK?
When should I move to a 3PL?
How long does it take to set up with a 3PL?
Do I lose control by outsourcing to a 3PL?
READY TO MOVE
Stop packing orders. Start growing the business.
Tell us about your operation and we'll come back with an ecommerce fulfilment setup and pricing built around what you actually need — no generic rate card, no surprises.
Trusted by ecommerce brands since 2003 · Two UK distribution hubs
