The hydro shield closure and coldcell insulation on this pick mean your food and drink will stay chilled for hours, even on a hot summer day.

This compact pick is perfect for a solo beach day or keeping your lunch at a cool temperature all day.

Designed with a waterproof tarpaulin shell and a puncture-resistant liner, this cooler will endure all your beach days to keep your food and drinks at a perfect temperature.

The cat is out of the bag: Today’s soft-sided coolers can insulate just as well as their hard-plastic counterparts. The best cooler bags are leakproof, too, meaning you can find all the benefits of a sturdy hard cooler in a bag that can be easily tucked away once emptied.

Soft coolers are also made to accommodate an array of uses, with models perfectly suited for quick lunch breaks or leisurely days alongside breaking waves. Before you seal the deal, however, here’s what you need to know when shopping for your next beach cooler, lunch cooler, or even cheap cooler.

No matter if you need them for play or work, the best cooler bags have one main job—maintain your food’s temperature. Bags accomplish this through insulation, leakproof seams, and other features. Just in time for you to pack that picnic, we’ve unpacked what you need to look for in a cooler bag.

Insulation is the primary way that the best cooler bags keep food cold—or hot, for that matter. Most bags feature thermal insulation, which keeps food or drinks at the desired temperature by stopping the transfer of heat. Think about it: If you place a hot mug of coffee on the counter, the beverage will slowly cool to room temperature. But if you put it in a concealed environment, it’ll transfer its heat energy to the inside of that space while simultaneously pulling heat energy from the air around it until the temperature of both the coffee and that concealed space settles somewhere in between.

A cooler bag’s insulation helps win the heat-transfer battle, and the best cooler bags use foam insulation. The gas bubbles in the foam, as well as the porous spaces between those bubbles, help slow heat transfer. But not all foam is the same. Open-cell foam is lighter and more flexible—making it an easier fit for soft-sided coolers. However, it doesn’t stop the transfer of heat as well as closed-cell foam, which does a better job of limiting the interaction between the gas bubbles. Brands such as Yeti have managed to create foam insulation that’s light and soft enough for bags, bringing the best of thermal to soft-sided coolers. Of course, expect to pay higher prices for technology that so effectively keeps the temperature up (or down).  

Seams are critical in a soft cooler bag, because they prevent leaks of all kinds. One type of leak is apparent—if the seams aren’t tight and your bag of marinating chicken spills, you’ll be cleaning your trunk, as well as your cooler. (Also, if you’re planning to dump ice into your insulated bag, weak seams could lead to a wet picnic blanket.)

While not as messy, the other kind of leak could be just as problematic. Remember, they work by creating a perfectly concealed environment to prevent heat transfer. Leaky seams compromise that environment by allowing air to flow in and out.

So what should you look for in a cooler’s seams? Rather than being stitched or glued together, the best cooler bags—the most airtight, that is—are welded together with heat and pressure. The seal on top of the bag also factors in. While zippers are most common—and perfectly suitable—Yeti has developed a magnetic seal that’s nearly as tight as a drybag. 

The outside of your cooler bag is important since that material determines waterproofing and other protections. A fabric’s deniability refers to the thickness of each thread, and anything above “1,000 denier” should provide ample resistance to water, mildew, and the sun. Many bags also feature breathable, elements-resistant linings—à la Gore-Tex.  

Soft bags can have as much capacity as blocky hard coolers. But if you’re planning to use it as a lunch box rather than a camping refrigerator, you’d be foolish to opt for the 30-can model. Still, a bigger bag can accommodate more ice, giving you the option of keeping food chilled for longer. Plus, the advantage of the best soft cooler bags over hard coolers is that they are packable, often folding down or rolling up in a way that lets them take up just a fraction of the space when they’re empty.

When your cooler bag is loaded with a case of beer and a bag of ice, you may need an extra set of hands. Models with handles, as well as shoulder straps, offer more ways—and more places—to grab and lift. Extra pockets are useful, too. Some bags have two insulated pockets, allowing you to keep your leftovers warm on top and your beer cold down below. Front and side pockets provide the perfect places to stash your dry goods or your keys. 

Related: What goes great with a cooler full of refreshing beverages? The best backyard games.

From the boat and the beach to the jobsite or campsite, insulated bags keep your food and drinks at your desired temperature. Here are the best cooler bags for no matter where you plan to be this summer.  

While the hunt for the abominable snowman may be ongoing, the search for the leading name in cooler bags stops with Yeti. And the Yeti Hopper M30 tops the brand’s offerings because of its versatility and durability. The wide-mouth, 25-inch by 12-inch by 17.5-inch cooler bag has room for 28 pounds of ice (or 20 beers) and weighs only 7 pounds when empty. To keep ice cold and beverages frosty, the insulated cooler bag features a leakproof magnetic closing system and closed-cell foam insulation inside. (Some reviewers do note that the dual-strip magnetic hinge on the Yeti Hopper M30 is actually too quick to close, making the bag hard to load.) Meanwhile, the bag’s outer shell is waterproof, prevents mildew, and is UV-resistant.

Made of 1,200-denier polyester, this durable lunch bag is built to resist water and protect your food. The bag’s thermal insulation will keep that helping of lasagne warm, or keep up to six beers cold, until you’re ready for a break—the bag clocks in at 10 inches by 9 inches by 7 inches and weighs less than 1 pound. The lunch cooler bag also has a second insulated top compartment, as well as a zippered front pocket for your dry goods or cutlery. And a carry handle and shoulder strap make this Carhartt lunch cooler bag easy to cart, no matter where the jobsite is.   

The stain-, tear-, UV-, and water-resistant tarpaulin shell is no doubt impressive, as is the 1,000-denier anti-skid canvas bottom, which prevents this beach cooler bag from sliding (or scratching) the boat deck. Then there’s the insulated pull-out liner (easy to clean) that’ll keep food hot or cold for 24 hours, and won’t rip or leak thanks to fusion-welded seams. But the feature that makes this the truly perfect beach bag is the fact that the soft-sided cooler—which comes in three sizes ranging from a capacity of 12 cans with a 5-pound bag of ice to 48 cans with two 10-pound bags of ice—can roll up into a quarter of its size. And when you’re sandy or soggy after a day on the water, there’s nothing better than having the haul-out be lighter and easier than the load-in.

The best thermal bags are designed to stop heat transfer, whether that means stopping your meatball sub from dropping in temperature or preventing your Coors Light from reaching Rocky Mountain high heat levels. And Yeti’s packable Daytrip Lunch Box provides all the versatility you need in a business and pleasure cooler bag. The 8.75-inch by 5.75-inch by 8.75-inch foldable bag has a closing hook that allows you to change its shape—from a standup lunch sack down to nearly flat. The Daytrip is a thermal bag lined with lightweight closed-cell foam, and it snaps closed with magnets for a tight seal.

Even on 90-degree Fahrenheit days, this Coleman soft cooler bag can keep 30 cans cold for 24 hours, because it has heat-welded leakproof seams and robust insulation. While hardly bulletproof, the nylon exterior has an antimicrobial lining designed to keep out odor, mold, mildew, and fungus. Plus, the ripstop fabric is made to prevent tears. That’s plenty of protection for a budget buy. The soft cooler bag also features side handles and an adjustable shoulder strap for easy transport, plus a front pocket to store your keys or bottle opener. 

Many soft coolers are waterproof. They feature protective shells or linings that also keep mold, mildew, and the sun’s rays at bay.

You can absolutely put ice in an insulated bag. The interior linings of the best options are completely leakproof, with seams that are welded together. Some even include pourable spouts, letting you easily drain water as the ice melts, without requiring that you take out all of your food or drinks.

Depending on the cooler bag you choose, your food can stay cold for hours or days. As a reference point, Coleman’s budget bag boasts that it can keep 30 cans cold for 24 hours. Of course, the quality of the insulation technology is important—with Yeti’s closed-cell foam, such as in the Yeti Hopper M30, leading the way—but size also matters. The bigger the bag, the more ice it can hold and, therefore, the longer your bag will have ice to keep your food cold.  

Related: These folding picnic tables give you a great place to unpack that cooler.

Whether you’re looking for frosty beers or fresher produce, an insulated bag is like a portable refrigerator that packs up easily when it’s emptied. With thermal bags’ foam insulation systems and airtight seals, the best cooler bags can keep your hot food warm and your cold cuts cool. The size and style you need depend on what you want to eat and drink and where you want to consume it. But no matter if you’re looking to tip back a few cold ones on a boat deck or eat a hot sandwich while constructing a client’s back deck, there is an option that’s right for you.  

is a Boston University journalism graduate with more than a decade of professional newspaper and magazine experience. Most recently, he worked full-time as an editor at Alaska Beyond, the inflight magazine for Seattle-based Alaska Airlines.

The best beach towels are a foundational piece of beach gear.

No matter where your adventures take you, cool down with the best coolers.

With extra-hot days on the rise, parasols are poised to reclaim their place in the sun.

Like science, tech, and DIY projects?

Sign up to receive Popular Science's emails and get the highlights.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. Registration on or use of this site constitutes acceptance of our Terms of Service.