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Finding the best ice packs for school lunch boxes is a tricky thing. So many are made with strange blue goo that's fine to cool down cans in our soft cooler but not exactly what we want touching grapes in our kids’ lunch boxes. Kids are also little, and a big chunky ice pack adds serious weight to their already loaded book bags. Plus, many of the newer styles of lunch boxes are thinner and we need to account for that. So I put a handful of ice packs to the test, from ones made with purified water to a stainless steel pack, and more traditional ice packs, to find out the best ice pack for kids' lunches.
Overall Best: Onyx Stainless Steel Ice Pack
This ice pack may be small—it’s the size of a small iPhone and looks like one too—but it packs a punch. We love that it’s stainless steel and not plastic, and it can fit easily inside a lunchbox (even the slim bento box that won our kids' lunch box test) or in an outer pocket. The price point is much higher than your typical ice pack so if your kids tend to lose stuff easily you may not want to make the investment until they're a little older.
Best Traditional Option: Healthy Packers Ice Pack
These are traditional ice packs with a few caveats. Although they do have “blue goo,” they are BPA free and non-toxic. They easily slide into the pocket of most lunch boxes and they're super lightweight and flat. They did a great job keeping the lunch cool but not freezing cold, which is great since my oldest child is, let's say very discerning, about the proper temperature of his food and will complain if it's too cold. They will also fit into the carrying cases of bento boxes (just not the boxes themselves). They don’t take up too much room in your freezer which is always a win. Plus, unlike the stainless steel ice packs, they're inexpensive, so it's not a huge deal if a few of them get lost.
Most Versatile: FlexiFreeze Ice Sheets
If you're worried about chemical-filled ice packs, these Flexifreeze sheets are the way to go. The plastic sheets are filled with pure water. You need to give them at least a few days in the freezer to freeze properly, but once you do but they are super versatile. You can cut the sheets to the proper size to fit your needs and they are the only ice packs I was able to fit into absolutely any bento box. I was also able to cut them small enough to just fit by the foods we wanted cold (no cold soggy chips here!) which was a nice plus. Some of the reviews say that they pop easily over time, but in my time testing I didn’t experience any issues.
How I Tested
Most school lunches happen within four hours or less of kids arriving at school so that was the time frame I used to test these ice packs. I used three lunch boxes filled with watermelon and a sandwich and I checked on the food hourly for temperature. I was looking for ice packs that allowed the food to stay cold enough that it was safe to eat—not the one that kept it the absolute coldest. I also tested for fit in a variety of lunch box styles and sizes. Finally, I sent the ice packs in lunch boxes with my kids to see how they worked in a real trip to the school cafeteria.
Factors I Evaluated
My kids hate when their food is too cold (and who really wants an ice cold sandwich?). The goal with these ice packs was to keep foods at a safe temperature, not actually chill them.
What were they made of?
We tried to test ice packs that were mostly non-toxic and BPA free, but even then, it was still hard to find out what exactly was in the blue goo on many of the options. Ideally, we'd find an ice pack with simple, nontoxic properties.
How did they fit in a variety of lunch box sizes and styles?
Did these ice packs work with multiple types of lunch boxes? Were they cumbersome and heavy? Bonus points if they could be small enough to chill certain components of the lunch and not others!
How easy were they to use?
I know this sounds strange. Don't you just put the ice pack in the lunch box and call it a day? Actually, some of these ice packs needed to be filled, others need to be cut to size, and others had specific instructions about being frozen for a certain period of time. Was the upfront work worthy of the outcome?
Other Ice Packs I Tested
These cooler shock ice packs kept things cold (almost too cold). They’d be fantastic for a bigger cooler but were too much (and too heavy) for a kid's lunch.
The Takeaway
Ice packs are somewhat dependent on the lunch box you choose. For a traditional option, the Healthy Packers are effective and inexpensive. For a stylish non-plastic option go for the Onyx Stainless-Steel Ice Packs, and for the option with the most size versatility, go with the Flexifreeze.
