Grey Mailing Bags 20×26" (508×660 mm) give serious room for pillows, bedding sets, bulky textiles and larger retail boxes while keeping parcels lightweight. Made from tough 60 µm co-extruded, 100% recycled LDPE, these self-seal postal bags are moisture-proof / water-resistant, fully opaque for privacy and recyclable via UK soft-plastic schemes. Most loads at this size ship as Royal Mail Medium Parcel or with couriers (Evri, DPD, Yodel). Check dimensions on the Royal Mail size guide.
Need a different fit? See all Grey sizes or browse the full Mailing Bags range. Prefer brand colour? Explore Coloured Mailing Bags.
Why this 20×26" size?
When 17×24" starts to strain, 20×26" adds the extra length and width you need for duvet covers, throws, towel bundles, knitwear stacks and mid-to-large retail boxes—without the dead weight of cartons. Neutral grey hides contents, resists scuffs and looks clean on arrival.
Real use examples (what typically fits)
- Textiles & home: bedding sets, pillows, throws, towel bundles, large cushion covers.
- Apparel: winter coats, multi-item clothing sets, bulky knitwear.
- Boxed goods: larger gift sets and retail boxes with a light inner wrap.
Fit & packing guidance
- Best fit: bedding/textiles, stacked apparel, bigger boxed kits.
- Too tight? Step up to 24×36" (or 28×30").
- Too roomy? Step down to 17×24" for a neater seal and lower postage.
- Corner care: pad sharp inner-box edges to reduce punctures.
- Press out air: flatten before sealing so labels sit flat and sacks/totes stack cleanly.
Key benefits
- Fast self-seal, tamper-evident closure — no tape needed for most orders.
- 60 µm co-extruded film — resists tears, splits and punctures in courier handling.
- Moisture-proof / water-resistant for wet routes.
- Fully opaque grey — privacy and a professional look on delivery.
- Lightweight — helps keep costs down versus rigid cartons.
- Recyclable LDPE (code 4) — remove glue strip before recycling.
Eco & materials
Material: 100% recycled LDPE (code 4), co-extruded for strength and opacity. Recyclable at many UK supermarket soft-plastic return points. Not biodegradable or compostable.
Strength & protection
The 60 µm film gives reliable puncture and tear resistance on bulky loads. The permanent adhesive forms a tamper-evident bond once pressed, protecting contents through warehouse and courier networks.
Storage & performance
Store flat at 13–21 °C away from heat/sunlight. Let cold stock reach room temperature before use for consistent seal strength.
Lightweight = lower postage
Mailing bags reduce dead weight and parcel size compared with boxes. At 20×26", many shipments route as Royal Mail Medium Parcel or via couriers; check service limits before dispatch.
Size comparison (choose the right bag)
| Size | Inches | Millimetres | Typical fit |
|---|---|---|---|
| Step down | 17×24" | 432×610 mm | Bedding sets, bulky textiles, larger kits |
| This page | 20×26" | 508×660 mm | Pillows, throws, multi-item apparel, bigger boxes |
| Step up | 24×36" | 610×914 mm | Very large textiles and retail boxes |
Buying guide: 17×24", 20×26" or 24×36"?
17×24" suits bedding sets and large apparel bundles. Choose 20×26" for pillows, throws and bigger boxed gifts (best “XL” all-rounder). Step up to 24×36" for very large textiles or retail boxes where the 20×26" seal feels stressed.
Common searches
20×26 mailing bags • extra-large grey poly mailers • waterproof postal bags • recyclable mailing bags UK • Royal Mail Medium Parcel packaging • bulk grey mailing bags • eBay and Amazon shipping bags
| Material | LDPE (code 4) |
| Size | 20x26 Inch (508x660 mm) |
| Color | Grey |
| Closure | Peel-and-Seal (Permanent) |
| Recyclability | Return to Supermarket Soft-Plastic Points |
| Thickness | 60 µm |
| Water Protection | Water-Resistant |
What fits in a 20×26" grey mailing bag?
Is 20×26" suitable for Royal Mail services?
Are these grey mailing bags waterproof?
Are 20×26" grey mailing bags recyclable?
How strong are 20×26" mailers for heavy textiles?
When should I choose 17×24" vs 20×26"?
When should I step up to 24×36"?
Are these bags fully opaque for privacy?
How should I store 20×26" grey mailing bags?
Do I need extra tape with 20×26" bags?
Royal Mail 24 Tracked
Dispatched same day if ordered before 5 pm Monday to Friday. Please allow up to 1-2 days for delivery.
£1.99
DPD Next Day
Dispatched same day if ordered before 3 pm Monday to Thursday. Not available to Scottish Highlands & Islands.
£4.99
Free on orders over £100