Best Breast Milk Storage Bags

As a nursing mother looking to store your breast milk, you have several options. Any freezer-safe, airtight container that you can sanitize will do the job, but not every storage method is equal in terms of convenience and ease of use.

Breast milk storage bags are specially-designed for exactly what their name would lead you to believe, and these little plastic pouches can save you time, effort and some space in the freezer or cooler bag.

Row of breast milk storage bags ready for the freezer

Different brands of bags have different features, so let’s take a closer look at multiple options to help you figure out which is the best breast milk storage bag for your needs. We’ll also cover general information about storage bags and the benefits they can deliver.

Our Top Picks at a Glance

Note: There’s a lot more information below but clicking the above links will take you to current prices, further information and customer reviews on Amazon.

What is a Breast Milk Storage Bag?

A breast milk storage bag is a sterile, single-use pouch specifically made for holding room-temperature, chilled or frozen breast milk. They typically have either a zipper or a screw-on closure that minimizes the chance leaks, and you can dispose of them in any appropriate garbage receptacle.

Many storage bags come with additional helpful features like volume measurements, a self-standing bottom and space for labeling.

Why Should You Use Storage Bags?

Advantages

Convenient

Breast milk storage bags can truly do it all. They are perfect for storing your milk in the refrigerator or freezer, and you can also thaw and warm your milk in the bag before transferring it to a feeding bottle. Some brands take the convenience factor a step further by attaching to your breast pump and directly collecting your milk, and a few brands even offer the appropriate connections that let you feed your baby from the bag itself.

Sterile

One of the nicest aspects of storage bags is that they come pre-sterilized, so you never have to spend time preparing your bag before you pour milk into it.
Many zip-top bags have a tear-off strip to ensure that your bag stays sterile until you open it, and most bags have individual seals for easy packing in the diaper bag or your pumping bag.

Easy to store

Thanks to the small size and flat design, you can organize and store a large number of bags in your refrigerator or freezer. Most bags also have a space for recording the pumping date, so you can rotate your stash to use the oldest milk first.

Disadvantages

Imprecise measurements

The ounce markings on the bag are a close estimation on the manufacturer’s part, but they aren’t reliable enough if you need to give your baby a specific, consistent amount of milk at each feeding.

Particularly if you pump directly into the bag, you may find that the amount of milk you’re feeding your baby differs from the measurement on the bag.

Potential for leaks

Unfortunately, a bag with a weak side or corner seam may be lurking in your box, and a zip-top could also result in spilled milk if you happen to miss a spot on the zipper.

How to Use Milk Storage Bags

Avoid Overfilling

It might be tempting to try to squeeze in a couple of extra ounces, but filling a bag beyond its upper volume capacity can lead to broken, leaky closures or a bag explosion in the freezer.

Leave plenty of room for the liquid to expand as it freezes, and make sure to unfold the bag’s bottom completely to use the bag’s full storage capacity.

Record Date and Volume on Bag

Breast milk has its limits for how long it can stay fresh in the refrigerator or freezer, and you don’t want to have to throw any milk out because it got too old or you can’t tell when you pumped it.

Make sure to record the date you expressed the milk, and use it within the recommended timeframe. Labeling each bag with the amount of milk it contains can help you make sure you set out enough milk for your baby’s meal or the whole day.

Remove Excess Air

Air takes up space, so failing to remove trapped air pockets can lead to a freezer explosion even if you’re careful with the amount of milk you store.

After pouring your milk into the bag, fasten the closure almost all the way. Apply gentle downward pressure on the bag to force any air bubbles to escape, and then seal the bag fully closed.

Never Re-Use a Bag

Since there is no way to effectively clean or sanitize them after use, breast milk storage bags are single-use only.

To avoid the temptation to re-use, pack a couple of extra bags with you if you have to pump away from home, and make sure to keep plenty of bags on hand at home.

Considerations When Buying Milk Storage Bags

Direct Pumping

Pumping your milk directly into a storage bag can save you time and energy by reducing the equipment you have to deal with and the number of dirty pieces you have to wash. A direct pumping capability may be especially helpful for moms who have to pump away from home.

If this feature sounds like a life-saver to you, make sure that the bag you are interested in is compatible with your specific breast pump.

Volume Capacity

Storing your milk in roughly meal-sized portions can help cut down on the amount of wasted milk, so the number of ounces that your child drinks at a feeding can be a helpful guide in determining what size bag might be a good choice.

Number of Bags to Have On-Hand

Thinking about how often you plan to pump and feed your child a bottle is the best way to determine how many storage bags you might need. To avoid wasting money by buying more bags than you end up needing or buying a large number of bags that you end up disliking, it’s probably a good idea to start with just one box.

Some brands offer their product in more than one quantity choice, and the option to order more or fewer bags based on your current needs can help you avoid running out or ending up with unused product.

Slim Design

Especially if you plan to build a large freezer stash, bags that you can store compactly can save a great deal of room. Zip-top bags tend to freeze flatter and take up less space than screw-top styles, so zipper bags might be a better choice if your storage space is on the small side.

Our Choices for the Best Breast Milk Storage Bags

Kiinde Twist Pouch

Packed with smart features, these storage bags from Kiinde can help reduce some of the extra supplies and time you’ll need if you plan to feed your baby a bottle frequently.

Any pumping mother is likely to be well aware of how much time it takes every day to wash multiple pumping bottles. With the addition of the appropriate adaptor pieces, you can reduce your cleaning time by directly attaching the Kiinde bags to your breast pump.

Another brilliant feature of these bags is that they snap directly into the Kiinde feeding bottles, so the entire pumping, mealtime and cleaning processes are greatly simplified.

We love that the screw-on closure does a great job of cutting down on leaks from faulty zippers. However, one downside to the twist-locking cap is that the bags don’t lay flat or stack as well as zip-top bags, so they will take up some extra space in the refrigerator or freezer.

Kiinde also uses thick plastic and gives their bags wide seams, so split bags and leaking at the seams should be at a minimum.

Manufacturer’s Specs

  • Volume capacity: Available in 6-ounce and 8-ounce options
  • Accommodates direct pumping: Yes
  • Available in multiple quantities: Yes
  • Type of closure: Screw-on cap
Things We Like
  • Eliminates the need for separate bottles
  • Twist-top closure
  • Can attach to a great pump directly
  • Two volume choices
Things we don’t like
  • Takes up more storage space

Summary

These clever storage bags can save you some precious time by eliminating the need to use and clean separate pumping and feeding bottles, and the screw-on top is easy to use while offering excellent leak resistance.

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Lansinoh Breastmilk Storage Bags

A beloved classic for many years, the Lansinoh breast milk storage bags have a simple design that offers reliable function.

To ensure that each bag maintains a sterile inner surface until you’re ready to fill it, Lansinoh added a perforated strip along the top of the bag that you’ll have to remove before use.

A double zipper on the closure strip reduces the chance for leaks, and a clever design creates a pouring spout that makes filling your baby’s feeding bottle easier and reduces the chance of spilling milk.

The self-standing bottom helps make filling these bags from a pumping bottle a bit easier, but you’ll still need to use one hand to support the thin plastic until you’ve poured in an ounce or two of milk. Lansinoh also manufactures an adaptor piece that allows you to directly pump into these bags with any Lansinoh breast pump or most other major pump brands.

One of our favorite aspects of this bag is that it truly freezes flat when filled with an appropriate amount of milk. Especially if you plan to pump frequently and store large amounts of milk, these bags can help you save space.

A potential for concern is the construction of the lower corners. These areas can have problems with leaking, so avoid creating undue stress on the bag from overfilling.

Manufacturer’s Specs

  • Volume capacity: 6 ounces
  • Accommodates direct pumping: Yes
  • Available in multiple quantities: No
  • Type of closure: Zipper top
Things We Like
  • Secure zipper closure
  • Adaptor piece allows for direct connection
  • Pouring spout reduces spills
  • Great space-saver
Things we don’t like
  • Seams may leak after freezing if the bag is very full

Summary

These storage bags do a great job of freezing flat and maintaining a sterile inner surface until opened. The lower corner seams can be a weak point with these bags, so be sure to avoid overfilling the bag and use care when defrosting frozen milk.

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NUK Simply Natural Seal n’ Go

These NUK bags offer smart design features that help cut down on the risk of leaking while also taking up a minimum of storage space.

We love that this bag has wide side seams and a smart, rounded bottom corner design that helps prevent leaks. The closure also has a double zipper for extra leak-proofing.

The rounded bottom gives this bag some enough stability to self-stand in the refrigerator or freezer. During the filling process, however, you’ll need to pour with one hand and hold the bag steady with the other to avoid the bag folding over. Fortunately, pouring your milk out of the bag and into a feeding bottle is an easier process thanks to upper corners that bend to form a handy spout.

As an additional purchase, NUK also offers a milk storage kit that includes an adaptor piece that allows you to pump milk directly into these bags. The top of the bag also has printed lines that make it easy to label your milk with your child’s name, the pumping date and milk volume.

Manufacturer’s Specs

  • Volume capacity: 6 ounces
  • Accommodates direct pumping: Yes
  • Available in multiple quantities: Yes
  • Type of closure: Zipper top
Things We Like
  • Double zip closure
  • Self-standing bottom
  • Upper corners form a pouring spout
  • Thick side seams shouldn’t allow for leaks
Things we don’t like
  • Need to use extra care when filling

Summary

With thick, well-designed side seams and corners, these bags do a good job of preventing leaks, but filling the bag can be a little tricky.

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Philips AVENT Breast Milk Storage Bags

With strong materials and solid construction, AVENT pulled out all the stops to prevent as many leaks as possible.

The plastic is a bit thicker than many other brands, and the zip top features a double-locking mechanism. AVENT’s side and bottom seams are also significantly wider than most other brands, so the risk of leaks should be dramatically less.

While you might struggle a bit to get all your desired information recorded in the tiny space some bags provide, you don’t have that problem with the AVENT bags. A large labeling area gives you plenty of space to write on four separate lines. One labeling feature we like is that the label faces away from the milk, so you’ll never have to try to balance your wrist over a liquid-filled surface.

One downside to this awesome labeling space is that it adds some extra height that you have to pour the milk through. Unless you have excellent aim during the filling step, you’ll probably end up with a little bit of milk in the zipper, and pouring milk into a feeding bottle can also be a bit challenging.

Manufacturer’s Specs

  • Volume capacity: 6 ounces
  • Accommodates direct pumping: No
  • Available in multiple quantities: No
  • Type of closure: Zipper top
Things We Like
  • Generous, thoughtful space for labeling
  • Reinforced, wide seams
  • Secure zipper closure
Things we don’t like
  • The tall top can make it hard to fill and empty the bag

Summary

With a strong zippered top, extra-sturdy seams and thick plastic, these bags are great at keeping every drop of milk you put in the bag where it belongs. However, these bags are a bit clunky to use.

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Milkies “No-Break, No-Leak”

The promise no breaking or leaking is certainly attractive to any pumping mother, and Milkies has worked hard to try to deliver on that claim.

We like the construction on the sides and lower corners. These can be problem areas on some other brands, but the Milkies design has strong, thick seams that are great at resisting leaks. However, although the zipper top has a double lock, it’s not full-proof and you may lose a bit of milk at the upper corners on occasion.

The upper portion of the bag has pre-printed spaces for recording the pumping date, milk volume and your child’s name. There is also a perforated tear strip at the very top of the bag that ensures a sterile inner surface. Milkies also added the cool feature of printing out breast milk storage guidelines on the front of each bag, so you have safe storing information at your fingertips at any time.

One thing we don’t like is the pouring-out process. After tearing off the top strip and storing your milk for a time, the bag’s upper portion tends to lose stability and curl over. This curling plastic can get in your way when you’re trying to fill a feeding bottle, so the process can require some dexterity and patience.

Manufacturer’s Specs

  • Volume capacity: 7 ounces
  • Accommodates direct pumping: No
  • Available in multiple quantities: No
  • Type of closure: Zipper top
Things We Like
  • Leak-proof side seams and lower corners
  • Thawing and feeding guidelines printed on the bag
  • Sturdy, thick plastic
Things we don’t like
  • Difficult to pour thawed milk into a bottle

Summary

These bags have a wonderfully strong side and lower corner design that all but eliminates the possibility of leaks from these areas. However, plan to use a little extra time and patience when filling a feeding bottle for your baby.

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Dr. Brown’s Breastmilk Storage Bag

If you plan to store your milk in the deep-freezer for a few months, these bags from Dr. Brown’s might be a great choice thanks to their thick, sturdy plastic and solid construction.

With wide side seams and securely sealed corners, you shouldn’t have any problems with leakage in these areas. Additionally, the top closure uses two sets of zippers for a secure seal that prevents milk from seeping out.

The strong material also lets the bag stand upright for easy filling, but make sure to unfold the gusseted bottom first to keep the bag from collapsing. When it’s time to fill your baby’s feeding bottle, the top corners function as a pouring spout to help reduce spills.

Due to it being on the decidedly small side, we don’t like the way Dr. Brown’s set up their labeling space. There are only two pre-printed lines for your child’s name and the pumping date, so plan to write in small letters if you want to include the milk volume or pumping time.

Manufacturer’s Specs

  • Volume capacity: 6 ounces
  • Accommodates direct pumping: No
  • Available in multiple quantities: Yes
  • Type of closure: Zipper top
Things We Like
  • The plastic material is sturdy and freezes well
  • Strong side and lower seams
  • Self-standing when opened properly
Things we don’t like
  • Labeling space is very small

Summary

These bags unitize thick plastic that is ideal for long-term deep-freeze storage, and the strong seams and double zipper resist leaking. Unfortunately, you don’t have much space for writing, so be sure to have a fine-tip permanent marker at the ready.

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Mommy’s Precious Breastmilk Storage Bags

Thanks to strong material and thoughtful construction, these bags from Mommy’s Precious can safely hold a bit more milk than many other brands.

Mommy’s Precious uses a thick plastic that can stand up to being packed in the freezer or cooler bag, and the wide side and corner seams prevent leaks. The zipper top has a strong double closure, so you shouldn’t have to worry about leaks from this area.

After you pour in about one to two ounces of milk, the gusseted bottom opens up and the bag will stand by itself while you pour in the rest of your milk. While these bags may not offer quite as much space for labeling, you do get the trade-off benefit of being able to easily pour milk into and out of the bottle.

One thing that can make these bags a little less convenient to use is the top tear-off strip. The plastic is a bit rigid, and if you don’t remove the strip carefully, you may end up tearing the bag itself.

Manufacturer’s Specs

  • Volume capacity: 8 ounces
  • Accommodates direct pumping: No
  • Available in multiple quantities: No
  • Type of closure: Zipper top
Things We Like
  • Sturdy plastic material
  • Easy to pour milk both in and out
  • The strong construction prevents leaks
  • Holds 8 ounces of milk
Things we don’t like
  • Can be hard to get open

Summary

These bags boast thick plastic material, a leak-resistant design and larger storage capacity than most other brands. However, make sure to spend some time perfecting your opening technique to prevent damaging the bag.

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Medela Pump and Save Breast Milk Bags

If directly pumping into your storage bag is a priority for you, Medela has you covered with their Pump and Save bags.

Each box of Pump and Save bags includes two adaptor pieces that attach to almost any Medela pump. Featuring a truly ingenious pump attachment and bag design, the adaptor has two hooked side pieces that fit into pre-made holes in the bag’s top portion, so pumping into the bag is as easy as opening the bag and hanging it on the adaptor hooks.

The bag itself has a solid construction thanks to thick plastic material and wide seams on the sides and lower corners.

Unfortunately, the milk volume capacity is on the low side at 5 ounces. Particularly if you have an over-supply of milk or your goal is to build a large freezer stash, plan to purchase quite a few of these bags.

The Pump and Save has only one zipper instead of the double zipper than many other bags use. Due to this design, you might run into some leaking issues if you overfill the bag at all or if you accidentally spill some milk into the zipper.

Manufacturer’s Specs

  • Volume capacity: 5 ounces
  • Accommodates direct pumping: Yes
  • Available in multiple quantities: Yes
  • Type of closure: Zipper top
Things We Like
  • Comes with direct pumping adaptor pieces
  • Thick plastic material
Things we don’t like
  • Holds less volume than most other brands
  • Single zipper closure

Summary

These bags from Medela have a clever construction that makes them easy to use for pumping at home or away. However, the storage capacity is small, and you’ll have to use extra care and attention to prevent leaks from the single zipper.

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Tommee Tippee Pump and Go Bags

With the capability to function as a collection, storage and feeding container, the Pump and Go bags are the central feature of Tommee Tippee’s well-designed feeding system.

The main benefit to these bags have to offer is that you can completely avoid any pouring or loss of milk from pumping, storing or feeding. With the purchase of a starter kit, these bags are ideal for direct pumping with almost any breast pump. The additional separate purchase of a feeding bottle shell allows you to snap the warmed bag directly into the bottle.

As opposed to a zipper that may skip or leak easily, the Pump and Go has a screw-on top that easily and securely keeps the bag sealed. The only downside is that the round top prevents these bags from freezing flat, and you’ll probably need some extra storage space to accommodate a large freezer stash.

While the feeding system is a convenient and smart concept, these bags also work well for traditional storage. You can pump into a collection bottle and then transfer the milk into the Pump and Go bag, but keep in mind that the small opening is a little harder to pour into without spilling.

Since these bags don’t have a flat top, they lack a dedicated space to record any information such as date or volume. However, you should be able to write directly on the bag with a permanent marker.

Manufacturer’s Specs

  • Volume capacity: 6 ounces
  • Accommodates direct pumping: Yes
  • Available in multiple quantities: Yes
  • Type of closure: Screw-on cap
Things We Like
  • Screw-on top eliminates the worry of a leaking zipper
  • Direct connections to breast pump and feeding bottle
Things we don’t like
  • The round closure takes up more storage space

Summary

The Pump and Go bags can serve multiple purposes with the purchase of appropriate adaptor pieces, and the screw-on closure offers a bit more security than the standard zipper.

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Unimom Thermal Sensor Bags

These storage bags from Unimom offer all the fundamentals of a standard zip-top bag with the addition of a clever thermal indicator.

The thermal-sensitive strip is solid blue while the milk is frozen, and the bar progressively becomes white as the temperature rises. While we love the idea of a built-in temperature sensor, the actual results seem to be a bit underwhelming. You probably won’t be able to use the bar to figure out when your milk is actually at a palatable warm temperature, but you should be able to tell at a glance when your once-frozen milk has thawed back into a liquid.

These bags offer solid construction with wide side seams and corners. Once you’ve poured an ounce or two into the unfolded bag, the self-standing gusseted bottom makes filling the bag the rest of the way a breeze.

A small writing area provides you with space to record the pumping date, milk volume and time, and a perforated tear-off strip lets you rest assured that your bag is sterile until you open it

Manufacturer’s Specs

  • Volume capacity: 7 ounces
  • Accommodates direct pumping: No
  • Available in multiple quantities: No
  • Type of closure: Zipper top
Things We Like
  • The thermal indicator is a clever idea
  • Sturdy design resists leaks
Things we don’t like
  • The thermal indicator’s functionality is limited

Summary

The concept of a temperature indicator is a great idea, but the function is mostly limited to showing whether the milk is in a frozen or thawed state. With strong seams, a self-standing feature and a top tear-off strip, these bags deliver good basic performance.

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Conclusion

Thanks to a simple design that has done the job well for many families over many years,
the Lansinoh breast milk storage bag comes in as our favorite.

The double zipper closure offers an extra measure of security against leaks, and the short top portion is perfect for pouring your milk into a feeding bottle. As long as you limit your milk volume to the recommended amount, you shouldn’t have problems with leaks at the seams.

A gusseted bottom gives the Lansinoh bags enough stability to self-stand during storage, but the bag still manages to freeze almost completely flat. Finally, the addition of an adaptor piece allows you to use your bag as a direct collection container with a wide range of breast pumps.

We want to hear your thoughts on breast milk storage bags! Have you tried any of these brands, or did you prefer another option? What did you like about your bag choice? What are some things you wish were different? Tell us about your experiences in the comments!

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