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2 plain square mailer boxes stacked on top of each other and one leaning up against them.
2 plain square mailer boxes side by side with the one on the left slightly open.
2 plain square mailer boxes stacked on top of each other and one leaning up against them.
2 plain square mailer boxes side by side with the one on the left slightly open.
Example 3 of selected product

Plain Square Mailer Boxes

Not looking for a custom design? Ship your products with these sturdy, budget-friendly unprinted boxes.
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Pack smarter with our budget-friendly plain square mailer boxes.

  • 2 size options
  • 1/8” white B-flute cardboard
  • Easy to assemble
  • Plain, unprinted boxes
  • Quantities from 12 to 600

Sturdy and reliable packaging

Skip the design process and get straight to shipping with our budget-friendly square mailer boxes. Made from sturdy, white B-Flute corrugated cardboard, these boxes are great for protecting your products while keeping things simple. Want to add a personal touch? Customize them with your own labels, stickers or custom print tape.

Easy to assemble and versatile

These sturdy, ready-to-ship boxes come in a couple convenient sizes. They save you time and effort while providing great protection for your products. Whether you’re sending apparel, artwork, books, or anything in between, these versatile boxes can handle it all.

Simple ordering process

Ordering your plain square mailer boxes is straightforward. Select the size and quantity you need, and we’ll handle the rest. That way you can focus on what matters most: creating a memorable experience for your customers. Rest assured that these sturdy mailers will help you deliver a reliable and professional shipping experience.

An open plain square mailer box.

Designs

Select a design template to preview it on the product. Click 'Continue' to customize it.

Reviews

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Ratings Distribution

Reviewed by 2 customers

LOVE THESE!

Aug 10, 2025 | Gwenna A. | Verified Buyer
Tried these out as I am rebranding and changing my packaging. LOVE THEM! Great quality. I shipped myself something heavy and breakable to test them out and all delivered without incident. Putting in an order for more right now.

Can’t wait to buy more!!

Feb 6, 2025 | Rhina T. | Verified Buyer
These boxes were great. I’ll be using them to mail prints to my Clients! They arrived in perfect conditions and our great quality!
Displaying Reviews 1-2

Frequently asked questions

At the moment the minimum order for our plain mailer boxes is 12.

You can customize your unprinted boxes with branded labels, stickers, or custom packaging tape that is self-adhesive or water-activated to make your package personalized and stand out from others.

See our overview section for a video that walks through assembling your box for the first time.

B-flute is a sturdy (1/8") corrugated cardboard making it excellent for protecting your goods. Sturdy and puncture-resistant, it’s a good option for shipments and you won’t need a secondary box when sending your items.

Yes. You can order sample mailer boxes in all our available sizes. We'll send a box pre-printed with a sample design for only $4 – and get free standard shipping when you use code SAMPLEBOX at checkout. This way, you can get a feel for the quality and try out different sizes before you order your one-of-a-kind design in bulk. Order your sample boxes now: Packaging Sample Kits & Prototypes | VistaPrint