What’s the Best Cooler for Breastmilk?

Breanna | Updated April 16, 2022 |

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What’s worse than spoiled milk? Spoiled milk that you took valuable time out of your day to pump, pour into cute little bottles, and label the exact time it was pumped

Pumping and breastfeeding is work, period. You can burn upto 700 calories a day doing it. Feeding is a diet in itself. So you need gear to preserve the fruits of your labor and breast milk cooler bags and storage bags are here to save the day and make your life a little bit easier. 

That’s why we’re giving our readers the lowdown on what features make a functional and convenient cooler bag and why. We’ve also rounded up some of the most popular choices in milk storage on the market and highlighted some of their shining features and drawbacks in our reviews. 

Our Picks – Best Cooler for Breastmilk

Note: Our individual reviews are below, but you can also click any of the links above to check current prices on Amazon and other retailers

Why do you need a cooler bag?

The simplest reason for needing a bag to store breast milk is the logistical struggle you encounter when carrying your work supplies, baby gear, baby, etc. You just don’t have enough hands to balance that load on the go. 

A breast milk cooler bag specifically designed to keep breast milk cold and prevent it from spoiling is valuable for more than just storage though. To maintain the safety of your milk for your baby, the temperature must be regulated. This is achieved with insulation and a cooler pack. Some specialized breast pump bags come with either matching cooler bags or cooler compartments.

Per the CDC, freshly pumped breast milk can be left at room temperature (77 degrees or cooler) for roughly four hours. Refrigerated milk can hang on for four days. The benefit to regulating your milk’s temperature is clear and ensures you preserve the fruits of your labor!

Who wants to waste milk that was allowed to heat up in a toasty office all day or was accidentally left to sour in a car? Keeping your milk in a convenient and best breast milk cooler saves you from extra work on several fronts. 

Does a breast milk cooler count as carry-on luggage?

Breast milk coolers do not count as carry-on luggage and pumps are regarded as medical devices, thus making them exempt as well. The TSA regards your liquid gold or breast milk the same way they do liquid medicine, meaning you don’t need to adhere to the 3.4 oz rule. 

With that being said, when traveling with breast milk you should notify the TSA agent of your milk and that it is being stored separate from other liquids and gels. Additionally, if you plan to store and transport a large quantity of milk, it’s a good idea to call ahead and clarify regulations. 

The CDC also recommends bringing a printed copy of the standard TSA regulations for transport to avoid confusion and misunderstanding in security. 

How long is breast milk good for in a cooler bag?

As long as you’re utilizing a frozen cooler pack, breast milk can be stored in an insulated cooler bag for up to twenty-four hours. Storage in a cooler bag might be a good option if you’re unable to store in the fridge at work or if you’re traveling. 

How do I know if my breast milk has gone bad?

There are certain telltale signs breast milk has spoiled. For instance, the layer of cream or fat that sometimes forms at the top of the milk (think about how foam on beer appears) should be able to be shaken and blended back into the rest of the milk. If it’s chunky, it’s probably not safe to drink anymore.

The other trademark sign of sour milk is something you’ve probably known since childhood. If the smell is rancid, so is the milk. Just like cow milk, breast milk should have a sweet aroma or none at all. 

If you’re still on the fence, you can always taste a bit of the milk. If it’s gone bad, the taste will be unmistakably sour. 

How many times can you re-warm breast milk?

Reheating breast milk should only occur one time. The valuable bacteria in breast milk can be broken down and destroyed with heat. Therefore, reheating shouldn’t be repeated over and over. 

For safety, milk should only be reheated and consumed within four hours. Just as room temperature milk is only good for four hours, so is heated milk. 

Heating should occur gradually with warm/hot water. Resist the urge to microwave the milk because it can create hot pockets within the bottle that can burn your baby. Microwaves break down the healthy nutrients in the milk as well. 

Can babies drink cold breast milk?

Will it hurt them? Probably not. Cool milk is fine for babies to consume, but they may enjoy it more if you warm it slightly by running the breast milk storage bags under some warm water. 

A benefit of heating the milk is the dispersion of the fat layer on top of the milk. You want your baby to consume the nutrient-rich layer of cream which is often harder to mix into cool or cold milk. 

Here’s an overview of milk storage and thawing best practices from Clarissa

What to look for in a good cooler bag.

Size/Carrying Capacity

Your preferences for size and capacity will likely be dependent on how much you plan on pumping. You may want a bag that’s small enough to fit within another pumping bag or one that can be tossed in the diaper bag if you need to pump on the fly. 

If you’re a professional pumper that’s penciled in several sessions throughout the day, it could be a good idea to look for a cooler bag large enough for several bottles and a reliable ice pack. 

In fact, if you plan on leaving your milk in the bag for several hours in any situation, it’s a good idea to ensure there’s room for a quality ice pack. You may want to check out bags for the added bonus of spare pockets to keep milk storage bags. Disposable storage bags allow you to date your milk and leave helpful reminders for yourself. They can be a handy addition to any pumping/feeding regimen.

It could be worth noting whether your cooler bag is part of a breast pump bag/cooler combination. Many breast pump bags come with a cooler bag for the same price and the deal ensures your cooler bag is compatible for storage within the larger bag.


Like the choices in breast pump bags, you may want to check out the overall aesthetic of your cooler bag. Often, breastmilk cooler bags can double as lunch boxes when they’re no longer used for milk. Many of the options on the market now cater to the evolving eye of fashion. 

How does it cool?

Most bags are recommended for use in combination with frozen ice packs. However, the insulation technology may differ from bag to bag. Some are lined with a simple but effective foil technology. Others may offer an additional layer of foam insulation. Most coolers are safe to store in the fridge. 

It’s always a good idea to check out the seal around closures. Any breach in the seal can cause cool air to leak out. 
As far as storage bags (plastic ziploc bags used for holding milk rather than a bottle), those are safe to freeze and when stored in a cooler will keep for hours. However, like any plastic bag they are prone to leaking. It could be useful to look for a cooler bag with interior pockets to keep storage bags upright.

Breastmilk Cooler Reviews

Medela Breastmilk Cooler and Transport Set

This Medela cooler bag fits conveniently into the tote that comes with purchase of the Medela Sonata, Freestyle, and Pump in Style breast pumps. Included with purchase are a contoured ice pack and four Medela storage bottles. Each bottle is 5 oz. 

This particular breast milk cooler bag advertises keeping milk cool for up to 8 hours which is more than sufficient to store your milk safely. The simple black design is also neutral and appealing. Even after your breastfeeding journey has concluded, this bag could be used to store small snacks and sippy cups for days at the park with your littles. 

What we liked:

  • Comes with four storage bottles
  • Contoured ice pack is included
  • Designed to fit inside pump bag

What we didn’t:

Doesn’t hold larger bottles with ice pack

Skip Hop Grab & Go Insulated Breastmilk Cooler

This option advertises enough room for two large bottles or sippy cups. However, the exact size in ounces isn’t specified. It comes with one soft gel ice pack to maintain temperature,

The interior is insulated in an easy-to-clean liner and features a pocket to store the included ice pack. 

Skip Hop offers several neutral prints for this cooler bag and each option features a convenient strap for clipping to diaper bags, pump bags, or strollers for storage on the go.

What we liked:

  • Tall enough to hold larger bottles or cups
  • Variety of prints that coordinate with diaper bags
  • Can be attached to other bags or stroller

What we didn’t:

  • The ice pack is soft gel and could be prone to puncture
  • Smaller ice pack may not keep bottles cool as long as a sturdy contoured ice pack 
  • May not be as efficient at keeping preheated bottles warm
Here’s a video overview from the Parent Panel of Skip Hop Grab & Go’s main features

Momcozy Multi-function Cooler and Lunch Bag

Momcozy offers a versatile bag with customizable features. The cooler compartment is detachable and allows for conversion into a larger single layer bag. When in use, the insulated cooler compartment is insulated and lined with waterproof interior, a soft sponge layer, and PEVA material. 

This breast milk storage bag cooler can hold up to six breast milk bottles at the height of 6 inches or shorter. It features a detachable buckle and an additional shoulder strap for functional carrying. However, this particular bag does not come with an ice pack and would require a separate purchase. 

It does offer the added bonus of extra pockets for storage and even an anti-theft pocket for convenient placement of your cell phone or car keys.

What we liked:

  • Convertible bag for bottles or lunches
  • Holds up to 6 bottles
  • Convenient straps attaching to diaper bag/stroller or shoulder carry
  • Extra pockets

What we didn’t:

  • Not as compact as other bags on the market 
  • Zippers may be prone to sticking

Sarah Wells Cold Gold

Coming in as one of the more stylish picks, this Sarah Wells cooler coordinates with the design/prints of their breast pump bags. All coolers are insulated with a waterproof easy-to-clean liner. 

The inside can comfortably fit up to 4, 8oz. bottles and the complimentary ice pack that comes with purchase. Their ice pack is a solid plastic design and comes with a lifetime guarantee. Sarah Wells endorses their cooler for at least 8 hours of cooling. 

They offer several stylish prints for moms that like to keep their gear stylish and the cooler fits inside their larger “Lizzy” bag.

What we liked:

  • Fits up to 4 bottles
  • Ice pack comes with purchase
  • Lifetime guarantee on bag and ice pack 
  • Several choices in print

What we didn’t:

  • Not as customizable as other options on the market (straps and buckles)
  • Might not be tall enough for larger bottles or sippy cups
Here’s a video review from Melina Brunson

FlexiFreeze Pocketbook Breastmilk Cooler

This bag features a unique cooling system with the ice pack built directly into the bag. On the smaller side, this bag fits two of the small hospital grade storage bottles and several of the plastic breast milk bags. 

Its compact design could be a functional choice for moms that don’t pump several times a day or wish to have a cooler that will fit into a smaller diaper bag or tote. 

This bag is also a convenient choice if your freezer is short on space. Just toss it in next to the frozen pizza you’ve had for the last year and the ice pack (made with 16 cubes of water) will be ready to go once solid. 

What we liked:

  • Ice pack is built in 
  • Smaller design fits into almost any bag
  • Throwing the entire bag into the freezer eliminates any chance of forgetting your ice pack

What we didn’t:

  • Smaller than other options and doesn’t hold full size bottles
  • Water ice pack doesn’t stay frozen as long as other gel options on the market

Breanna is a former therapist turned writer. She earned a master’s in psychology in 2015 but ultimately decided she would like to be more present for her family. Currently flexing her writing skills as a stay-at-home mother of two toddlers (with another baby on the way), she enjoys writing in the parenting and home/DIY niches. She also writes fiction and has been published in a handful of literary magazines and a fiction anthology. In her spare time, Breanna enjoys blogging, painting, running, and drinking an absurd amount of coffee.


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