Costco's confusing new checkout rules leave shoppers scratching their heads

When you've paid your annual membership fee and planned your monthly bulk shop around those famous Costco savings, the last thing you want is to be turned away at the checkout because of a rule nobody told you about.

Yet that's exactly what's happening to shoppers across Australia, starting with Costco Marsden Park's new self-checkout restrictions.

The Sydney store has quietly introduced a '10 items or less' rule for self-checkout lanes, alongside a ban on 'oversized items' - and customers are understandably divided about what this means for their shopping experience.

The rule that's spreading (inconsistently) across stores

Many regular Costco shoppers report being annoyed by the enforced item limit at self-checkouts, which varies from store to store.

What's happening at Marsden Park isn't isolated—it's part of a patchwork of policies being implemented across different Costco locations, both in Australia and internationally.

The problem? 'All I want is consistency. If Costco is going to enforce a number, do so—note what the number of items is, and enforce it consistently across stores.'

That sentiment from frustrated shoppers captures the core issue: some stores enforce five-item limits, others allow 10, and many still have no official restrictions at all.

Costco doesn't have an official item limit for self-checkout. But just because there's no hard rule doesn't mean there aren't unwritten ones—and this non-policy policy does cause some confusion for customers and employees alike.

Why the sudden crackdown?

The reasons behind these new restrictions make sense from a business perspective, even if they're frustrating for shoppers.

Imposing a limit on self-checkout can be a loss prevention tactic for many stores, as Costco employees say that the self-checkout lanes are where the majority of thefts occur.

Fewer items allowed at self-checkout means fewer high-value products sneaking through unpaid.

There's also a practical space issue. The small area for scanned purchases simply can't accommodate upwards of 20 items.

It's not as simple as moving the items directly into shopping bags on the ground after scanning because items have to stay on the scale until after you pay.

But perhaps most importantly, Costco policy says that the person checking the receipt at the exit door must count every single item on a self-checkout receipt. So if you have 42 items on your receipt, then it's going to take extra time.

What counts as 'oversized' anyway?

Here's where the confusion really kicks in. When you're shopping at Costco—a store literally built around bulk buying—what exactly qualifies as an 'oversized item'?

The good news is that your regular bulk purchases are likely fine. Many experienced shoppers believe 'oversized items' would be the furniture and that sort of thing, not paper towels or other typical bulk household goods.

However, this interpretation isn't officially confirmed, leaving shoppers to guess what they can and can't take through self-service lanes.

The simultaneous membership crackdown

While stores are implementing item limits, Costco is also tightening enforcement around membership cards at self-checkout.

'Stores have begun checking membership cards against picture IDs in the self-checkout line,' and employees are now stationed at self-checkout to ensure the membership card does in fact belong to the person making the purchase.

This affects families who might have traditionally shared a card between spouses or adult children. Costco is cracking down on card sharing so much that even if their spouses stood next to them at checkout, they could not use each other's membership cards.

What this means for your shopping routine

For many seniors who have built their shopping routines around Costco's bulk buying advantages, these changes require some adjustment.

The key is understanding that self-checkout is increasingly being positioned as an express option rather than a full-service alternative.

Most employees recommend sticking to 10 items or less, which means your big monthly shop will likely need to go through a staffed checkout lane—and that's perfectly fine. The benefit is potentially faster service for those quick trips when you just need a few items.

To have the best Costco self-checkout experience, stick to a small number of items. Have your membership card and payment method at the ready.

Don't expect to use a hand scanner, as many locations don't make those available to customers. As always, be ready to present your receipt to an employee at the door before leaving.

A word of caution about consistency

The most frustrating aspect of these new rules isn't the restrictions themselves—it's the lack of consistency between stores. Different stores see different traffic from location to location, and most are busier on weekends versus weekdays, which explains why policies vary.

Before your next Costco trip, it might be worth calling ahead to ask about current self-checkout policies at your local store. This can save you the frustration of having to abandon your self-checkout plans and join longer queues at staffed registers.