Poly Mailers Guide: Why Use Them, When to Use Them, and How Much They Cost

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Poly mailers. Bubble mailers. Poly bags. Plastic bags. Mailing bags. Poly bubble mailers.

Whatever you call them, they have gained a lot of popularity in the ecommerce shipping world.

Choosing the right packaging or mailing envelope for shipments will determine everything from shipping costs to whether products arrive safely at the customer’s doorstep.

If you’re paying too much for shipping, you may never get a positive return on your customer acquisition cost. If a customer orders from you and they realise a product is damaged during the unboxing experience, they may never order from you again.

While you may associate cardboard boxes with online shopping, many orders don’t come in a box at all.

Poly mailers are a common packaging option because they can protect certain products with built in cushioning at a lower cost than corrugated cardboard packaging.

In this guide, we’ll go over how poly mailers work, when to use poly mailers instead of boxes, and how to get poly mailers.

What are poly mailers?

Poly mailers are lightweight but sturdy plastic bags designed to ship products. They have a self-sealing foldover lip so no tape is needed, and a shipping label can be directly affixed on the bag. They are thin, yet durable so they don’t take up much space on a truck while in transit.

Poly mailers come in many sizes and styles with some being padded with bubble wrap so they don’t require additional dunnage like many boxes require to hold items in place to prevent shipping damages.

Poly mailers vs. boxes: why should I use poly mailers?

Boxes are a staple for shipping, but they can be unnecessary for shipping certain products. For example, shoes are often packaged in strong cardboard boxes, so shipping them inside another cardboard box wouldn’t make sense.

Apparel is also a great option for poly mailers as clothing isn’t susceptible to being crushed or broken without a box. Here are a few reasons why you might consider using a poly mailer instead of a box.

Significantly cheaper shipping costs

While corrugated boxes are sturdy, cheap, and resistant to damage, poly mailers provide protection while reducing shipping costs. Due to their light weight and small size, poly mailers cost less per shipments when compared to boxes.

One major factor in the pricing of shipments is dimensional weight, a pricing technique used by shipping couriers where they charge whichever number is greater: the actual weight of the package or its calculated dimensional weight.

This way, couriers can charge more money for a lightweight package that takes up a lot of room on the truck. They also have surcharges for heavyweight shipments, so keeping packages small and light is in any ecommerce company’s best interest.

Poly mailers take up less space than boxes, so they help reduce dimensional weight to help you save even more on shipping costs. The more shipments that go out in a box that could go out safely in a poly mailer, the more shipping costs will eat into your margin over time.

Smaller and lighter

Since poly mailers are made out of plastic, they’re much easier to store from a warehousing standpoint. Their small size also means they take up less space in courier’s vehicles, so you pay less for shipping too.

When it comes to delivery, poly mailers can sometimes fit in a mailbox, which reduces the chance of theft as compared to a package that’s sitting on a porch.

Custom branding options

Custom packaging that uses your branding helps your shipments stand out. Like boxes, poly mailers can include your logo, colours, and imagery if you desire a sleek look.

Boie's noissue compostable bags that ShipBob shipsEco-friendly options

While you might think plastic poly bags are a terrible option for the environment, there are many packaging companies that provide eco-friendly packaging options for poly mailers.

If your brand foundation is built on an environmental-conscious mission, it wouldn’t look suitable for your brand to use standard plastic mailers. You can use everything from recycled poly mailers to biodegradable poly mailers like ShipBob customer Boie does (picture to the right).

eco-friendly packaging

Opt for a little extra padding

Shipping damages are an unfortunate reality that can be prevented in many cases. Some poly bags come with a bubble-lined interior to maximise security. These bubble mailers provide an extra layer of protection for products, though they won’t fully protect fragile items, they can be a good alternative if you’re worried regular poly mailers may damage certain items.

Which types of ecommerce products can be shipped with poly mailers?

Poly mailers are a good option for any products that can’t be crushed like apparel or fabric, or useful for products that are already in sturdy packaging like shoes that you don’t think will stay sealed while in transit. If it passes the test of ‘Will this product be okay if a courier throws the poly bag into a pile that gets heavy boxes tossed on top of it?’ then you can use a poly mailer.

Poly mailers should never be used for fragile items like sunglasses, foods such as chips that can be smashed and crumbled, and products made out of glass. Unless these products are already in sturdy packaging, stick to boxes.


Poly mailers are great for apparel because it’s hard to crush clothing. When fulfiling apparel orders, you want to use poly mailers for products like jeans, shirts, or footwear that aren’t at risk of being crushed while in transit. However, if you sell dresses with intricate beading or ornaments on them, they’re better suited for boxes.

“Before ShipBob, we used a fulfilment centre that frankly couldn’t scale with us. This speed and scalability is important, because as soon as we announce a new pair of shorts, they sell quickly. Since moving to ShipBob we’ve grown 30% year over year, which is a testament to their scalability, service, and technology. I feel really fortunate to have found ShipBob when we did.”

Carl Protsch, Co-Founder of FLEO

Cloth and fabric-based products

Like apparel, most products made of cloth, cotton, or any type of fabric are good candidates for poly mailers. Ideal products include swatches, yarn, face masks, and bedding products like sheet sets.

Books and printed media

Books are a good option for poly mailers as they’re often already sturdy. A bubble-lined poly mailer can provide the extra security needed to prevent rips and dents in the book when shipping books with a poly mailer.

Some health, beauty, and wellness products

Fulfilment for health, beauty and wellness products can be done in both boxes and mailers, but it’s ultimately dependent on the product’s packaging and materials.

Liquid products like face wash and products in glass aren’t good for poly mailers, but shipping vitamins and supplements, nutrition products, and cosmetics (e.g., shipping makeup like a tube of mascara, liquid eyeliner, or lipstick) may be done in poly mailers so long as the they are sealed tight and already encased in materials that won’t break when dropped or thrown.

“We use noissue for our eco-friendly mailers that are 100% compostable, and ShipBob ships orders out for us in our custom branded packaging. ShipBob is a fulfilment partner that is truly an extension of our brand.”

Manuel de la Cruz, CEO at BOIE

Anything else in strong, sturdy product packaging or that’s soft and flat or not easily crushed

One of the reasons brands use poly mailers is to ship products that are already in sturdy packaging. It’s often overkill to ship products in cardboard boxes if the product is already packaged in cardboard.

Other examples of sturdy packaged products include:

  • A deck of playing cards
  • Smaller board games
  • Phone cases

4 types of poly mailers

There are several types of poly mailers available, and the type you use will depend on your goal(s), whether that’s to save money, showcase your brand, be eco-friendly, or play it safe and add more protection.

Regular white poly mailers

These standard plastic poly mailers have no bubble padding. They are your most cost-effective option and best suited for products that don’t need more cushion like bubble wrap. They cover the product and don’t offer much protection.

Bubble padded

These poly mailers come bubble-padded on the inside to provide extra security for any high-quality products that require it or for those that you are worried could get scratched.

Expansion poly mailers

These are your heavy duty poly mailers, made from strong polyethylene and designed to protect products from moisture during shipping. They are puncture, moisture, tamper, and tear-resistant and feature padded bottoms to allow for thicker items.

Eco-friendly options

Eco-friendly poly mailers include biodegradable and recycled options. For eco-conscious brands, these are the poly mailers to use as they minimise waste, maximise the use of renewable energy during production, and are safe for both consumers and the environment throughout its lifecycle.

Where can I get poly mailers?

Poly mailers are available for purchase at just about any location that sells shipping supplies. Some of the most popular places to get poly mailers include:

  • Australia Post (at your local post and online)
  • FedEx (at retail store locations and online)
  • UPS (at retail locations and online)
  • Walmart (at retail locations and online)
  • Target (at retail locations and online)

If you choose to work with ShipBob for outsourced fulfilment, we provide poly mailers for shipments at no extra cost. If you want custom branded poly mailers, our partners like noissue can help.

Pick the perfect packaging for all your products with ShipBob

With ShipBob, you get best-in-class ecommerce fulfilment services, support, and technology. You can choose between poly mailers and boxes on a product-by-product basis. Even if you have a diverse set of products, you can still choose boxes for more fragile products or combinations of fragile and non-fragile items.

“We use ShipBob’s locations that optimise and reduce the distance travelled to get our products into our customers’ hands faster. When shipping glass bottles, especially in the winter, the longer the transit time, the more likely it is to break. We see that our customers are getting their packages safer, with fewer frozen bottles exploding.”

Lindsay Louise, Fulfilment & Retail Manager at Synchro

We also have custom packaging vendors who can help create branded poly mailers for you to help your brand stand out even more.

ShipBob has a unique custom box algorithm that predicts the best packaging option based on the product weights and dimensions as well as the merchant’s packaging preference they set in our proprietary software.

To help optimise costs, when our fulfilment centre staff are packing orders, they get a validation message that makes sure we are not placing orders that could potentially ship out in a poly mailer or bubble mailer in a box.


Not every product has to be shipped in a box. Poly mailers are a great packaging option for small ecommerce businesses shipping to save even more money while ensuring products aren’t damaged.

Contact ShipBob by clicking the button below and learn more about how ShipBob can help you with retail fulfilment while growing your ecommerce business.

How much are poly mailers?

While poly mailers may be a good alternative to boxes, we still see confusion about how poly mailers work and why they’re useful. Below are some of the frequently asked questions about using poly mailers.

Does Walmart sell poly mailers?

Prices can vary from $0 (for some instances of free shipping supplies) to a few dollars per pack of 25. USPS poly mailers can ship for no additional cost if you have small shipments. If you’re a ShipBob customer, poly mailers are available at no extra cost for your shipments.

Does USPS have poly mailers?

Yes, Walmart sells poly mailers. You can purchase them online or in store.

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Written By:

Kristina is the Sr. Director of Marketing Communications at ShipBob, where she writes various articles, case studies, and other resources to help ecommerce brands grow their business.

Read all posts written by Kristina Lopienski