Glossary
Mailing bags
Definition
Lightweight bags, in plastic or paper, with a self-seal strip for posting non-fragile items. They are light and slim, which helps keep postage down.
Also known as: Mailer bags, Poly mailers, Postal bags, Courier bags
Mailing bags are flexible, self-sealing envelopes used to post soft or non-fragile goods such as clothing, textiles and accessories. Made from polythene, paper or padded constructions, they weigh very little and add minimal bulk, which helps items stay within cheaper Royal Mail size and weight bands.
Plastic (poly) mailers are waterproof, tough and often available with recycled content, while paper mailers offer a plastic-free, kerbside-recyclable option, and padded versions add light protection. Most have a peel-and-seal strip and many include a second adhesive strip for easy returns.
Because they offer little rigidity or cushioning, mailing bags are not suited to fragile or crushable items, which are better in a box, sometimes with void fill. For soft goods, though, they are cheaper, lighter and slimmer than boxes, and the paper-versus-poly choice usually comes down to protection, waterproofing and recyclability.
What to check
- Use bags for soft, non-fragile goods, not crushable items.
- Choose poly for waterproofing, paper for kerbside recyclability.
- Check the micron or gsm suits the weight and security you need.
- Look for a returns seal strip if customers post items back.
- Confirm the packed bag stays within your target postage band.
Need help choosing the right spec?
Tell us what you're packing and your quantities — we'll recommend the right size, grade or material and price it for your order.
Mailing bags — FAQs
Are mailing bags suitable for fragile items?
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