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Poly and kraft bubble mailers serve the same basic function but differ in ways that matter for specific items and shipping conditions. Poly mailers dominate for good reason, but kraft has a real niche — particularly for sellers whose brand presentation and eco credentials matter to their customers. Here's the honest comparison.
Head-to-Head Comparison
| Property | Poly (Plastic) | Kraft (Paper) | Winner |
|---|---|---|---|
| Water resistance | Excellent — fully waterproof outer layer | Poor — kraft paper absorbs moisture, weakens and tears when wet | Poly |
| Puncture resistance | Good — poly film resists tearing and puncture under normal handling | Moderate — kraft paper is more easily punctured by sharp corners, sorting machinery | Poly |
| Cushioning/impact | Good — polyethylene bubble layer absorbs shock effectively | Moderate — honeycomb paper or crinkle paper cushions but less than bubbles | Poly |
| Weight (mailer itself) | Light — poly mailers add minimal weight | Heavier — paper-padded mailers can add 30–60g vs poly equivalent | Poly |
| Recyclability in Canada | Poor — laminated plastic not accepted in most blue bins | Good — paper-based, accepted in paper recycling or compost | Kraft |
| Brand presentation | Generic industrial appearance | Natural, craft appearance — preferred by many independent sellers | Kraft |
| Cost per unit (bulk) | Lower — typically $0.25–0.55 per unit at 100+ qty | Higher — typically $0.35–0.75 per unit at 100+ qty | Poly |
| Printability | Requires special poly labels; direct printing difficult | Accepts direct printing well; standard labels adhere cleanly | Kraft |
The Canadian Winter Test
This is something that often gets skipped in generic comparisons written for American audiences, but it's genuinely relevant for Canadian sellers: kraft mailers are vulnerable to moisture, and Canada has wet winters.
When packages sit on a snow-covered porch, pass through sorting facilities with wet conveyor belts, or spend time in an outdoor collection box in a February rainstorm, kraft mailers get damp. A damp kraft mailer weakens significantly — the paper softens, the honeycomb padding compresses, and the mailer becomes susceptible to tears that a dry mailer would resist. For October-through-March shipping, especially to addresses in Atlantic Canada, the Prairies, or anywhere with meaningful precipitation, kraft mailers carry a real risk of arrival damage that poly mailers handle without issue.
Here's the practical winter difference: poly survives slush, wet porch boards, and light snowfall with almost no change in performance. Wipe it off and the contents are usually fine. Kraft does not. Even a brief soak from melting snow can soften the seams and corners. If the parcel then gets dragged across a sorting belt or wedged into a community mailbox, the weakened paper is much more likely to split. That failure mode matters most for books, paper goods, greeting cards, textile items that mildew if damp, and anything with sharp corners.
Some sellers address this by placing the item in a poly bag inside the kraft mailer, which preserves the aesthetic and eco appeal while waterproofing the item itself. This adds a step and some cost, but it works. Another compromise is seasonal switching: kraft from April through September, poly from October through March. That approach makes more sense in Canada than treating packaging as a static year-round decision.
Use Case Guide — What to Ship in Each
Ship in Poly When:
- Shipping electronics, devices, or anything moisture-sensitive
- Winter months, especially to remote addresses
- Item needs strong puncture resistance (sharp edges, pointy components)
- Fragile items where maximum bubble cushioning matters
- Keeping shipping weight low for borderline letter-rate items
- You need the lowest possible per-unit cost
Ship in Kraft When:
- Your brand identity emphasizes sustainability
- Shipping books, clothing, fabric goods where moisture exposure is low-risk
- Spring/summer shipping domestically in Canada
- You want curbside-recyclable packaging and communicate that to customers
- Shipping to buyers who've asked about sustainable packaging
Price Comparison at Bulk Quantities
| Quantity | Poly (#2 size, avg) | Kraft (#2 equiv., avg) | Cost Difference |
|---|---|---|---|
| 25 units | ~$0.65–0.80/ea | ~$0.80–1.05/ea | ~20–30% more for kraft |
| 100 units | ~$0.40–0.55/ea | ~$0.55–0.72/ea | ~25–30% more for kraft |
| 500 units | ~$0.28–0.38/ea | ~$0.38–0.52/ea | ~30–35% more for kraft |
Approximate Amazon.ca and bulk supplier pricing; varies by brand and exact size. Prices as of early 2025.
At 500 units, the cost difference on a #2 mailer is roughly $50–70 total — noticeable but not prohibitive for a seller who ships that volume. For very high-volume sellers (5,000+ units), the gap widens enough to require a real business decision about whether the eco/branding benefit justifies the cost.
Recyclability in Canadian Municipalities
This is where a lot of product marketing gets slippery. Sellers hear terms like "recyclable," "paper-based," or "eco mailer" and assume curbside blue-bin acceptance. In most Canadian municipalities, that assumption is wrong.
Poly bubble mailers: Most municipal blue box programs reject them. The issue is not just that they're plastic — it's that they're a multi-layer mailer with bubble padding, adhesive strip, and mixed films that regular curbside systems are not set up to separate. Toronto, Calgary, Edmonton, Winnipeg, and many smaller municipal programs do not want poly bubble mailers in standard recycling carts. Some flexible plastic depots accept certain clean plastic films, but bubble mailers usually do not qualify. In practical terms, most poly mailers are landfill unless a specialty depot explicitly says otherwise.
Kraft bubble mailers: Slightly better, but still not simple. If the mailer is truly paper padded with no plastic bubble lining, some municipalities will accept it in paper recycling. But many so-called kraft bubble mailers are actually paper outside with plastic bubble inside — and those are also rejected by many curbside systems because residents cannot separate the materials. Compostability claims are also often overstated; adhesives and interior padding can disqualify them.
For more on eco options specifically, see eco-friendly bubble mailers in Canada. For sizing reference, see the full size guide. If you're still deciding based on actual inventory, the common mistakes section on our homepage covers the sizing and Canada Post thickness errors that cost sellers the most money.