You’re standing in the middle of a Costco warehouse, dodging a forklift and trying not to buy a giant sectional sofa you don't need, when you hit the canned goods aisle. It's overwhelming. There are towers of Kirkland Signature white albacore, but right next to them sits the familiar blue and white packaging of Costco Chicken of the Sea tuna.
Most people just grab the Kirkland brand because, well, it’s Costco. But if you look closer at those Chicken of the Sea packs—specifically the 7-ounce cans—you’ll notice they occupy a weird, specific niche in the pantry-stocking world. It isn't just about price. It’s about the moisture content, the flake size, and whether or not you’re actually getting more fish for your dollar or just more salt water.
Honestly, tuna is one of those things people get weirdly defensive about. Some swear by the premium "solid white" texture, while others just want something that doesn't smell like a harbor at low tide when they crack the lid.
The Math Behind the 7-Ounce Anomaly
Most grocery stores sell 5-ounce cans. That’s the industry standard. It’s been that way since the great "shrinkflation" waves of the early 2000s when the old 6-ounce cans vanished. But the Costco Chicken of the Sea tuna packs usually come in a 12-count of 7-ounce cans.
Why does that matter?
It changes the ratio of your mayo-to-fish mix. If you’re used to a standard recipe, dumping two of these 7-ounce cans into a bowl gives you 14 ounces of protein. That’s nearly a pound of tuna. It's enough to feed a family of four without having to crack open a third can and leave half of it drying out in the fridge under a piece of aluminum foil.
The price per ounce is where Costco usually wins, but you have to be careful. Sometimes the Kirkland Signature 7-ounce cans are priced almost identically to the Chicken of the Sea. When that happens, the choice becomes a matter of texture rather than pennies. Chicken of the Sea tends to be "Chunk Light," which is a mix of smaller tuna species like Skipjack. It’s darker. It has a stronger flavor. Kirkland is typically Solid White Albacore, which is firmer and milder.
If you’re making a tuna melt where the cheese is doing the heavy lifting, the Chunk Light is fine. If you’re eating it straight out of the can with a fork like a college student in a dorm, you might notice the difference.
What's Actually Inside the Can?
Let's talk about the liquid.
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There is a massive debate among tuna aficionados—yes, they exist—about the "press." When you buy Costco Chicken of the Sea tuna, it is packed in water. When you drain it, you lose a significant portion of the weight. Some independent tests by consumer advocates have shown that "Chunk Light" varieties often have a higher water-to-fish ratio than "Solid White" varieties.
Chicken of the Sea has been around since 1914. They know how to process fish. The tuna at Costco is wild-caught, which is a standard marketing term, but it’s important to look at the sourcing. Most of this fish comes from the Pacific or Indian Oceans.
Mercury and Safety Concerns
Everyone worries about mercury. It's the "boogeyman" of the seafood world.
The general consensus from the FDA and the EPA is that Skipjack (the primary fish in Chunk Light) has lower mercury levels than Albacore. This is because Skipjack are smaller and lower on the food chain. They don't live as long, so they don't bioaccumulate as much of the heavy metals.
If you are someone who eats tuna three or four times a week, the Costco Chicken of the Sea tuna might actually be the safer bet over the "fancier" Albacore. It's a trade-off: you get a slightly "fishier" taste, but you get a lower chemical load.
Sustainability and The Thai Union Connection
Chicken of the Sea is owned by Thai Union Group. They are one of the biggest seafood players on the planet. For a long time, Greenpeace and other environmental groups were on their backs about "FAD" (Fish Aggregating Devices) which lead to high bycatch rates. Basically, they were catching turtles and sharks along with the tuna.
To their credit, they’ve cleaned up a lot. They now have a "SeaChange" sustainability strategy. When you buy these packs at Costco, you're usually getting fish that is traceable. You can actually go to their website, plug in the code from the bottom of your can, and see which boat caught your dinner. That’s a level of transparency you didn't see ten years ago.
Comparing the Texture: The "Mush" Factor
Cheap tuna is mushy. There is no way around it.
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When you buy the bulk pack of Costco Chicken of the Sea tuna, you are buying a product designed for volume. It isn't hand-packed fillets. It’s processed.
- The Flake: It’s small. It works perfectly for sandwiches because it spreads easily.
- The Color: It varies from light tan to a pinkish-grey. Don't expect the pearly white of a $5 individual can of boutique tuna.
- The Smell: It’s present. It isn't overwhelming, but you'll want to rinse the can before you throw it in the recycling bin.
If you’re making a Tuna Nicoise salad for a dinner party where the fish is the star, don't use this. Buy the jarred tuna in olive oil. But if you’re making tuna salad for school lunches? This is the workhorse of the pantry.
The Hidden Value of the Multipack
Costco sells these in 12-packs. That seems like a lot of tuna. It is a lot of tuna.
But canned tuna has a shelf life that rivals a twinkie. Most cans are marked with a "Best By" date that is three to five years out. In reality, as long as the can isn't dented, rusted, or swollen, the protein inside is shelf-stable for a very long time.
In 2026, with food prices fluctuating wildly, there is a legitimate "prepper" value to having a flat of tuna under the stairs. It’s 14 grams of protein per serving. It requires no cooking. It’s the ultimate emergency food that actually tastes like something.
How to Get the Most Out of Costco Chicken of the Sea Tuna
If you find the flavor of the Chunk Light a bit too strong, there’s a trick. Drain it thoroughly. Then, soak the tuna in a bit of cold water or even milk for about five minutes. Drain it again. This pulls out some of the "fishiness" and leaves a cleaner slate for your seasonings.
Another thing: don't sleep on the lemon juice. The acidity cuts right through the metallic tang that sometimes accompanies canned fish.
- Drain the 7-ounce can using the lid as a press. Get it dry.
- Add a teaspoon of Dijon mustard instead of just straight mayo.
- Use celery seed. It provides that nostalgic "deli" flavor that chopped celery alone can't achieve.
- Fold, don't stir. Even though Chunk Light is already small, you don't want to turn it into a paste.
Is the Kirkland Brand Actually Better?
The "Kirkland vs. Brand Name" war is real. For many, the Kirkland Signature Solid White Albacore is the gold standard of warehouse tuna. It’s firmer. It’s prettier.
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However, the Costco Chicken of the Sea tuna often goes on "Member Only Savings" rotation. When that $3 or $4 coupon hits, the price gap becomes massive. We’re talking about a difference of 30% to 40% in cost. At that point, the "better" tuna is the one that leaves more money in your gas tank.
Also, some people actually prefer the softer texture of the Chicken of the Sea. If you have kids who are picky about "chunks" in their food, the softer flake of the Chunk Light blends into the mayo better, making it less of a texture issue for sensitive eaters.
Practical Steps for Your Next Costco Trip
Before you toss that blue 12-pack into your flatbed cart, do a quick audit.
Check the "Price Per Ounce" on the shelf tag. Don't look at the total price. Costco is great about labeling the unit price, which is the only way to compare a 12-pack of 7-ounce cans to an 8-pack of 5-ounce cans.
Check for dents. Because these are shrink-wrapped in plastic rather than sold in cardboard boxes, the cans on the edges of the pallet often take a beating from the forklifts or other carts. A dented seam is a safety hazard—bacteria love a compromised seal.
Finally, think about your consumption. If you aren't going to eat 12 cans in a year, you’re just cluttering your pantry. But if you're a high-protein eater or a parent packing daily lunches, this is one of the most consistent values in the warehouse.
Actionable Insights:
- Audit your recipes: If your standard tuna salad recipe feels "watery," it’s likely because of the 7-ounce volume difference. Adjust your mayo and relish ratios accordingly.
- Track the sales: Chicken of the Sea at Costco typically goes on sale at least twice a year. Stock up during these windows; the shelf life makes it a zero-risk investment.
- Safety first: Always choose Chunk Light (Chicken of the Sea) over Albacore if you are pregnant or feeding young children, due to the lower average mercury content in Skipjack tuna.
- Check the seal: Inspect the plastic wrap on the 12-pack. If it’s loose or torn, check the individual cans for "puffs" or lid flexibility, which indicates a spoiled seal.
The Costco Chicken of the Sea tuna might not be the most glamorous item in the store, but it represents the core of the warehouse club philosophy: high volume, decent quality, and a price point that makes the membership fee feel worth it. Whether it's for a post-workout snack or a budget-friendly family dinner, these oversized cans remain a staple for a reason.