Patenting for Inventors Ep.159: Lululemon Sues Costco - A Fashion Lawsuit You Can’t Just Downward Dog Out Of
Illustration by @max_gps
In this episode of Patenting for Inventors, partner Adam Diament unpacks a headline-making case in the world of fashion law: Lululemon Athletica v. Costco.
The lawsuit, filed in June 2025, accuses Costco of selling copycat versions of Lululemon’s signature designs — from the SCUBA® hoodie and DEFINE® jacket to the ABC pant. Lululemon’s claims include:
Design patent infringement over hoodie details and ornamental features
Trade dress violations tied to the look and feel of its iconic products
Trademark infringement, including use of “Scuba” and even color names like “Tidewater Teal”
Unfair competition under California law, alleging Costco is profiting from consumer confusion and the rise of “dupe culture”
Could this lawsuit change how courts view fashion lookalikes, or will Costco successfully argue that these features are simply part of broader industry trends?
🎧 Listen to the full episode to hear Adam break down the claims, defenses, and what’s at stake for both sides.
Patenting for Inventors Ep. 159:
Podcast Transcript:
Hello and welcome to the Patenting for Inventors Podcast, the podcast where intellectual property law meets real life, one yoga pant at a time! This episode is “Lululemon sues Costco. A Fashion Lawsuit You Can’t Just Downward Dog Out Of.” I’m your host, Adam Diament, and today we’re breaking down a lawsuit that could change how big retailers copy—or “get inspired by”—premium fashion brands.
We’re talking about the 2025 case of Lululemon Athletica v. Costco, filed just this past June. It’s a real showdown between the boutique yoga brand that made $120 leggings cool, and America’s favorite big-box wholesaler—where you can walk out with a treadmill, a rotisserie chicken, and apparently, some suspiciously familiar activewear.
Lululemon is going all in here: alleging design patent infringement, trade dress infringement, trademark infringement, and unfair competition under California state law. This isn’t just about one product either. They’ve called out hoodies, jackets, and pants—multiple brands across Costco’s private-label and partner lines.
So, what’s Lululemon claiming? What will Costco likely argue in response? And who really has the stronger legal stretch? Let’s take a closer look.
What Lululemon Says Costco Did
Lululemon claims that Costco is selling blatant knockoffs of its most iconic products. Specifically, they name six allegedly infringing garments:
The Danskin Half-Zip Pullover and Hoodie,
The Jockey Ladies Yoga Jacket,
The Spyder Women’s Yoga Jacket,
The Hi-Tec Men’s Scuba Full Zip, and
The Kirkland 5 Pocket Performance Pant.
These are supposedly lookalikes of Lululemon’s SCUBA® hoodie, DEFINE® jacket, and ABC pants—products that are heavily promoted, widely sold, and closely tied to Lululemon’s brand identity. Some of these products, Lululemon says, even used identical color names, like “Tidewater Teal,” that are strongly associated with its own line.
What makes this more than just a fashion beef is that Lululemon isn’t just saying Costco copied their general “look.” They’re saying Costco is infringing design patents, violating registered trademarks, and copying trade dress—the unique look and feel of their garments that consumers recognize as being Lululemon’s signature. They’re also bringing in California’s Unfair Competition Law, which gives them one more way to argue that Costco is unfairly profiting off their brand reputation.
The Design Patent Claim: Strong on Paper, Weak in Court?
Let’s start with the design patents. Lululemon owns two design patents—D989,442 and D1,035,219—covering the ornamental look of its SCUBA® hoodie. These protect features like the unique shape of the kangaroo pocket, curved seams, and a specific textured panel layout.
Design patents are theoretically powerful. If a competing product looks “substantially similar” to the patented design in the eyes of an ordinary observer, where the ordinary observer thinks that what they’re buying is the same thing shown in the design patent, that’s infringement—even without proof of copying. And in this case, Costco’s Danskin pullover and hoodie bear a strong resemblance to the patented SCUBA designs, at least according to the side-by-side images in the complaint.
But here’s the reality check: design patent lawsuits in fashion are notoriously difficult to win. Courts often find design elements “functional” (which isn’t protectable) or “obvious” based on prior designs. What looks unique in an Instagram ad can seem mundane in federal court.
Costco will almost certainly argue that any similarities are superficial or dictated by function. They’ll also emphasize small design differences—different seam curves, pocket shapes, or branding—that might be enough to avoid infringement. They could also argue the design is anticipated by older garments, especially if they can find similar activewear in the public domain. Anticipated is the legal word that means it’s already existed before filing a patent application.
Lululemon’s strength here is the specificity of its design patents and the strong visual similarity in some cases. But its weakness is that courts tend to interpret design patents narrowly, and judges don’t always see hoodies the same way fashion editors do.
Trade Dress – A Battle Over Brand Identity
Central to Lululemon’s case is their claim that Costco infringed on the trade dress of three product lines: the DEFINE® jacket, SCUBA® hoodie, and ABC pants.
Trade dress refers to the overall look and feel of a product that consumers associate with a specific brand. Think: the curved seams on the DEFINE jacket, the distinct back panel of the SCUBA hoodie, or the gusset layout on the ABC pants. Lululemon argues these aren’t just design choices—they’re visual signatures. And it’s gone further by actually registering the DEFINE jacket’s trade dress with the USPTO, which gives them a stronger legal footing.
The challenge with trade dress is always proving distinctiveness. You have to show that consumers associate these design features with your brand specifically. Lululemon does a solid job here—they cite years of use, celebrity endorsements, social media buzz, and a ton of unsolicited media coverage.
Another big hurdle is functionality. You can’t claim trade dress rights in features that are primarily functional. So even if the curved seam looks cool, if it helps the jacket fit better or makes it easier to sew, it might not be protectable. Lululemon tries to head that off by saying these features actually increase manufacturing complexity and aren’t needed for performance—but courts will scrutinize that closely.
Costco’s likely strategy? Attack the distinctiveness and argue functionality. They’ll say features like pockets, curved seams, or gussets are common and expected in activewear. They’ll also point out differences in fabric, labeling, or fit. And they’ll argue that Lululemon’s designs are part of broader fashion trends, not unique to them.
This part of the case is likely to be the most contentious—and the hardest to predict. Trade dress cases can go either way. Lululemon has a strong branding story, but Costco only needs to show that the designs are functional or not distinctive enough to avoid liability, or that Costco’s designs are slightly different so there’s no actual confusion.
Trademarks – Names and Colors in the Crosshairs
Now let’s talk about classic trademark infringement. Lululemon owns the registered mark SCUBA® for hoodies and other apparel. Costco sells a men’s product labeled “Hi-Tec Men’s Scuba Full Zip”—and Lululemon says that’s confusingly similar.
Here, Lululemon’s got a decent shot. If “SCUBA” is widely recognized as a Lululemon brand, then even using the word in a descriptive sense (as Costco likely intended) can be problematic. That said, “scuba” could be considered generic or highly descriptive in term in fashion, often used to describe neoprene-like material. That ambiguity could give Costco some cover.
Then there’s the color name TIDEWATER TEAL™, which Lululemon says has acquired common law trademark protection. Apparently, some Danskin hoodies were sold under that same name. Lululemon claims that “Tidewater Teal” is distinctive enough to identify its brand, but they’ve never federally registered it. That makes this a harder claim to win.
Costco could argue they had no idea the color name was protectable—or that it was a common industry term. But Lululemon is betting that the accumulation of all these similarities—design, styling, and naming—adds up to consumer confusion.
The Wild Card: California’s Unfair Competition Law
Finally, there’s California’s Unfair Business Practices Act. This law casts a wide net. You don’t have to prove design patent infringement or trademark confusion—you just have to show that Costco’s conduct is misleading or unfair.
This is where Lululemon’s broader narrative comes into play. They cite articles from The New York Times and The Washington Post that literally ask: “Is this a Lululemon dupe?” They point to TikTok influencers using #LululemonDupe hashtags on Costco products. They say consumers are being misled—at the point of sale and after—into thinking they’re buying something Lululemon-related.
This is a psychological confusion claim. Even if the tags don’t say “Lululemon,” even if the price is different, even if you’re buying it next to a 12-pack of tomato sauce—it still creates brand association that Costco allegedly benefits from unfairly.
This is probably Lululemon’s strongest overall claim, because it allows them to blend all their arguments together—design similarity, branding mimicry, marketing language, and consumer perception. Costco will likely respond that they sell under different brand names, use their own marketing channels, and have never claimed any connection to Lululemon.
But courts sometimes view this kind of aggregation skeptically—especially when dealing with functional clothing in a crowded marketplace.
Who Has the Upper Hand?
So, who’s more likely to win this thing?
Lululemon has strong branding, a loyal customer base, and some registered rights—particularly with the SCUBA and DEFINE names and designs. They’ve taken the time to register trade dress, file design patents, and build a compelling case. They also frame the lawsuit not just as IP enforcement, but as protection against the normalization of knockoffs.
Costco, though, has the advantage of ambiguity. They sell under different names, they didn’t use Lululemon logos, and they can argue that most of these features—curved seams, four-way stretch pants, zip-up jackets—are just part of modern activewear trends and aren’t exactly the same as the ones on Lululemon clothing. That might be enough to create legal distance, especially in the eyes of a court wary of turning fashion into monopoly territory.
Lululemon’s best chance is to emphasize consumer perception—that people see these Costco clothes and think Lululemon. That’s powerful, but it’s also hard to prove without surveys, testimony, and a judge who really understands modern branding.
Costco’s best defense is functionality, descriptive use, and non-exact reproductions. If they can frame everything they’ve done as part of a general market trend, not an attempt to mimic one brand specifically, they could skate by.
If I had to call it now? It’s close, but I’d probably side with Costco for most of the claims. Lululemon has a well-pleaded complaint, but the outcome will likely hinge on how the court interprets consumer confusion and functionality—two areas where fashion law has historically been slippery.
Also, winning fashion claims are an uphill battle based on some previous cases. Take Christian Louboutin v. Yves Saint Laurent — the battle of the red soles. Louboutin claimed its signature scarlet bottoms were being knocked off by Yves Saint Laurent. The court kind of gave them a win… but with an asterisk. Louboutin got trade dress protection only when the red sole contrasted with the rest of the shoe. So if Yves Saint Laurent makes an all-red heel? Totally fair game.
Then there’s Abercrombie & Fitch v. American Eagle — the preppy showdown. Abercrombie & Fitch basically said, “Hey, American Eagle is biting our style!” But the court wasn’t having it. Turns out that khakis and polos just aren’t all that unique. And when Coach sued Target over lookalike handbags, the court reminded everyone that being “inspired by” isn’t the same as “infringing.” Bottom line? Unless a brand’s look is truly iconic and consumers can spot it blindfolded, judges tend to say, “Nice try, but trends aren’t trademarks.”
That said, not all hope is lost. There have been wins — like in L.A. Gear v. Thom McAn, where L.A. Gear successfully sued over a copycat high-top sneaker. The court agreed that the overall look of the shoe — including things like the molded heel piece, color striping, and placement of design lines — had acquired secondary meaning and wasn’t just functional. That case showed that if a brand builds strong visual identity around a non-functional style, it can protect it — even without a logo. But to be fair, cases where the plaintiff wins is the exception, not the rule.
Final Thoughts
This case isn’t just about yoga jackets or men’s pants. It’s about how far a brand can go to protect its look and feel in a market saturated with fast fashion and low-cost alternatives. It’s about whether the law should prioritize consumer access to cheaper lookalikes—or reward the innovation and brand-building that premium companies like Lululemon invest in.
Win or lose, Lululemon is sending a clear message: “If you try to ride our waistband coattails, expect a knock at the courthouse door.” Most cases actually don’t go to court either, so there’s a good chance that there will be a settlement, if Costco has the stronger arguments.
That’s it for today’s episode of Patenting for Inventors. If you enjoyed this deep dive, send it to a friend, post it to your dupe discussion thread, and tune in next time as we untangle more legal drama at the intersection of innovation, branding, and commerce. If you need help navigating intellectual property such as patents, trademarks, copyrights, or business matters, give me a call at 424-281-0162. Until next time, I’m Adam Diament, and keep on inventing.