What Costco actually turned on
On September 17, Costco became available across the full DoorDash Marketplace in the United States, giving members same day delivery of groceries, pantry staples, household essentials, electronics, and seasonal merchandise from any of its 647 US and Puerto Rico warehouses. Each location is stocked with more than 4,000 products for the service, according to reporting from The Shelby Report. Mike Goldblatt, DoorDash's vice president of enterprise partnerships, framed it plainly: "Costco members have been asking for Costco on DoorDash, and today we're delivering."
The US rollout extends a partnership that already covers Australia, New Zealand, Sweden, Iceland, and Puerto Rico, per PYMNTS. Goldblatt's second line is the more revealing one for operators: "By pairing Costco's quality, value and selection with DoorDash's reach and local delivery network, we're giving members more flexibility in how they shop." That is a warehouse club, built on bulk purchases and a membership fee model, explicitly ceding the delivery layer to a third party network it does not control.
The warehouse club holdout finally caves
Warehouse clubs were the last major US retail format resisting the same day delivery buildout that grocery and general merchandise chains completed years ago. The bulk pack, low margin, low SKU velocity model does not map cleanly onto a courier picking a single order from a pallet-stacked floor built for cart-loading members rather than professional pickers. Aisles are wide and stocked for pallet jacks, checkout is built around massive basket sizes, and store staff are trained for member service, not order-picking throughput. Costco's years of hesitation reflected a genuine operational mismatch between the format and the delivery model, and rushing into it earlier would likely have produced a worse member experience than waiting for a mature third-party marketplace to solve the problem instead.
Competitive pressure explains the timing better than any internal cost breakthrough does. The same week, Uber Eats expanded its own Costco integration to 47 states, a detail Shelby Report notes was announced one day before the DoorDash news. Costco chose to run two delivery marketplaces in parallel rather than consolidate onto a single partner, a hedge that maximizes coverage and negotiating leverage. That hedge carries a cost: Costco now depends on two external routing and fulfillment systems it has no engineering control over, and any service failure on either platform lands on Costco's brand regardless of who owns the courier.
Renting the last mile instead of building it
Every retail CTO eventually faces the same build versus rent decision on delivery: invest years and hundreds of millions into proprietary logistics, the Amazon and Walmart+ path, or plug into a marketplace and get to market in months. Costco, with $297.3 billion in fiscal 2026 revenue up 10.2% year over year, unquestionably has the capital to build its own stack. It chose not to, and that choice is the actual news here, more than the delivery feature itself.
The rationale is straightforward capital discipline. Warehouse club economics run on thin margins and high inventory turns, and diverting engineering headcount into a delivery routing and fleet management problem that DoorDash and Uber have already solved at scale is a poor use of scarce technical talent. For a reader weighing a similar build versus buy call on any commodity capability, Costco's move is a useful data point: even a cash-rich incumbent decided the differentiation was not worth owning.
Who owns the customer when you outsource fulfillment
The trade-off Costco accepted is data and relationship control. DoorDash sees the order timing, basket composition, delivery windows, and repeat purchase cadence of Costco members shopping through its app, signal that used to belong exclusively to Costco's own membership analytics. DoorDash now partners with eight of the ten largest food retailers in North America, which means it is quietly assembling a cross-retailer view of grocery demand that no single retailer, including Costco, can see on its own.
That asymmetry matters more as retail media and predictive personalization become core profit centers rather than side projects. A retailer that routes orders through a third party marketplace is handing that party the exact behavioral data needed to build the next generation of targeting products, the kind Sam's Club and others are racing to build in-house. Costco's membership model gives it some insulation since its own signup and renewal data stays proprietary, but the marginal order now flows through someone else's platform first.
The margin math on bulk goods and last mile courier economics
Bulk retail was built around the assumption that the customer absorbs the cost of transporting a 36-count paper towel case home in their own vehicle. Handing that same case to a courier on a per-order delivery fee model inverts the unit economics that made the warehouse club format profitable in the first place, since a single delivery vehicle now has to carry the volume and weight that a member's own SUV or pickup truck previously absorbed for free. Neither Costco nor DoorDash disclosed fee structures in the announcements we reviewed, which is itself notable given how central delivery fees are to whether this channel is profitable for either party, or whether it is being subsidized as a customer acquisition and loyalty play in its early months.
Retailers running thin-margin categories through delivery marketplaces need real visibility into contribution margin per delivered order, not just top line GMV growth, before declaring a channel a success. The absence of published pricing here suggests Costco and DoorDash are still working out who absorbs the cost of serving bulk-format baskets through a delivery model designed for single-meal restaurant orders and grocery run-outs, a materially different logistics problem in terms of vehicle capacity, load time, and route density per stop. Any technology leader evaluating a similar partnership should insist on a shared unit economics model before launch, broken out by basket size and category, rather than discovering the true cost structure a year into the relationship once volume is already locked in.
What this means for your own delivery roadmap
If your organization is debating whether to build proprietary last mile capability, Costco's move argues for renting first and re-evaluating once volume and margin data justify vertical integration. Marketplaces like DoorDash and Uber have already absorbed the fixed cost of courier networks, routing algorithms, and driver supply, and replicating that from scratch rarely pencils out below a certain order volume threshold, especially for a format like warehouse clubs where delivery is a new capability layered onto an existing, already-optimized in-store model rather than the core of the business.
The counter-argument is the data dependency this creates. Before signing a marketplace delivery deal, negotiate explicit data-sharing terms covering order-level signal, not just aggregate reporting, and build the internal analytics muscle to act on whatever data you do retain. Costco's scale gives it negotiating leverage most retailers lack, and smaller operators entering similar deals should assume the marketplace will keep the richest signal for itself. Plan your own customer intelligence roadmap around the data you can realistically secure in the contract, rather than the data you would ideally want, and revisit the build versus rent decision again once delivery volume through the marketplace reaches a scale where owning the stack starts to pencil out.
