How to Pack Parcels Properly in 2026 – UK Mailing Bag Packing Guide

Introduction: Why Proper Parcel Packing Matters in 2026

In 2026, customers expect parcels to arrive quickly, cleanly and without damage. If packing is poor, the cost is not just a torn bag or a late delivery. It can mean returns, refund requests, lost stock, negative feedback and fewer repeat customers. In UK eCommerce, your packaging is part of your brand — even if you sell on marketplaces and not your own website.

This guide is written for UK sellers who want a simple, reliable packing method that works with Royal Mail and major couriers. It focuses on using mailing bags properly for clothing, gifts and everyday online orders. You’ll learn what to use, how to pack step-by-step, when to choose a box instead, and the common mistakes that cause damage in transit.

What Are Mailing Bags?

Mailing bags (often called postal bags or postage bags) are lightweight, waterproof outer packaging used for shipping soft and non-fragile items. They are popular because they reduce postage costs, protect against rain, and speed up packing in busy dispatch environments. In most UK shipping setups, mailing bags are the default choice for clothing, textiles, accessories, and some books.

At Mr Bags, you can shop the full range in our Mailing Bags collection, including our best-selling Grey Mailing Bags and colour options like Blue, Green, Pink and Purple.

Why Mailing Bags Matter in UK E-Commerce

Mailing bags solve three big UK eCommerce problems:

• Postage cost control – They are lighter than boxes, helping you keep costs down.
• Weather protection – UK deliveries face rain and damp conditions year-round.
• Fast dispatch – Peel & Seal bags reduce packing time, especially in high order volumes.

They also help customers because parcels are easier to open, easier to store, and often easier to return (depending on your returns process).

Benefits of Mailing Bags When Packing Parcels

• Lightweight – reduces shipping cost and improves handling.
• Water-resistant – protects from rain and moisture in transit.
• Opaque – supports privacy (important for clothing and personal items).
• Peel & Seal closure – simple to seal and tamper-evident.
• Space-saving – easier to store than boxes.

For many UK sellers, mailing bags are the simplest way to pack professional-looking parcels without slowing down dispatch.

What You Need Before Packing a Parcel

Before you pack anything, set up a small packing station. Even if you are packing orders from home, a simple routine reduces mistakes.

• Correct size mailing bags (avoid forcing items into tight bags)
• Labels (printed or handwritten, but always clear)
• Optional reinforcement like Packaging Tape
• Optional inner protection (tissue, paper, or a secondary bag for premium presentation)
• Boxes for fragile or rigid items (see Cardboard Boxes)

The goal is consistency: same packing method, every day, every order. That’s how you reduce damage and customer complaints.

How to Choose the Right Mailing Bag Size

Choosing the right size is the biggest factor in preventing tears and split seams. If a bag is too small, you’ll stretch the film and weaken the seal area. If it’s too large, your parcel can look messy and labels may crease.

Two of the most popular sizes for UK clothing sellers are:

• 12×16 – ideal for hoodies, jeans, small clothing bundles: Grey Mailing Bags 12×16
• 13×19 – ideal for bulkier apparel, joggers, multi-item fashion orders: Grey Mailing Bags 13×19

If you want a simple “default” for fashion parcels, start with 12×16 and add 13×19 for larger orders. Both sit naturally inside most standard dispatch workflows.

How to Pack Clothing Safely in Mailing Bags

Clothing is the easiest category for mailing bags, but it still needs a method. The aim is to keep the parcel flat, reduce movement, and avoid pressure on the seal.

1. Fold clothing flat so it sits evenly. Remove excess air.
2. Keep sharp items separate (zips and buckles can catch and rub through film).
3. Place heavier items at the bottom so the seal area stays stress-free.
4. Leave clearance at the top (do not pack right up to the seal strip).

Quick rule: If the item presses against the flap area, the bag is too small. Size up. A slightly larger bag is better than a stretched bag that risks tearing in transit.

How to Pack Books, Gifts and Soft Home Items

Mailing bags work well for books and gifts if you manage corners and weight correctly.

• Books: Put the book inside an inner wrap first (paper or a protective sleeve), then place into a mailing bag. Keep the book centred so corners do not rub against seams.
• Gifts: Use clean inner packaging for presentation. For in-person gifting, you can also use Paper Bags before placing the order into a mailing bag for postage.
• Textiles: Fold neatly. If the item is bulky (towels, bedding), avoid forcing it. Size up or consider a box.

This simple approach reduces scuffs, corner damage and complaints like “item arrived scrunched” or “packaging looked cheap”.

How to Seal a Mailing Bag Properly

The Peel & Seal strip is designed to be quick, secure and tamper-evident. Most “opened in transit” complaints happen because the seal wasn’t pressed down properly or the bag was overfilled.

1. Remove the liner fully so the adhesive is exposed end-to-end.
2. Close the flap straight — do not seal at an angle.
3. Press firmly along the full width of the seal.
4. Pay attention to the corners (these are the first weak points if rushed).

If you are shipping heavier items, you can add a single strip of packaging tape across the seal for extra reassurance, but do not rely on tape to fix an overfilled bag. The correct fix is always: choose the right size bag.

Label Placement: Royal Mail and Courier Best Practice

Correct label placement prevents scanning issues and delivery delays. Labels should always be:

• Flat (no wrinkles or bubbles)
• Fully visible (not across seams or folds)
• Not covering the seal strip
• Not wrapping around an edge

For Royal Mail guidance on size and handling, use the official reference here: Royal Mail size and weight guide. It’s worth keeping this bookmarked if you ship daily.

If you regularly send parcels with Royal Mail, our Royal Mail parcel guide for mailing bags explains size limits, posting rules and how to avoid surcharges.

Mailing Bags vs Boxes: When to Use Each

Mailing bags are best for soft items. Boxes are best for rigid or fragile items. The mistake many sellers make is trying to use mailing bags for products that really need a box.

If you are unsure, use this simple rule: if the item can be crushed or snapped, use a box from our cardboard boxes range. If it’s soft and flexible, a mailing bag is usually right.

Retail vs Business Packing: What Changes?

Retail sellers (low daily volume) often pack more slowly and focus on presentation. Business and trade sellers (higher volume) focus on speed, consistency and cost control. Both can use the same core method, but business packing needs:

• Standard sizes kept in stock (like 12×16 and 13×19)
• A repeatable packing process
• Fast seal and label workflow
• Clear quality checks before dispatch

If you ship at scale, it’s worth keeping a core bag size that covers most orders, then adding a second size for larger parcels. That reduces errors and speeds up dispatch.

Trade & Wholesale Packing: How to Keep It Fast and Clean

For trade and wholesale orders, parcels are often heavier and may include multiple items. This is where packing choices matter most. The key is to prevent movement inside the parcel and protect corners. Many trade sellers pack goods into a box first, then use a mailing bag as an outer layer for weather protection and privacy.

If you are sending mixed items (for example clothing plus accessories), keep rigid items separate or boxed so they do not press against the mailing bag film.

Environmental Impact: The Truth About “Less Waste” Packing

Packaging is not eco-friendly if it fails in transit. When a parcel arrives damaged, the waste increases: replacement stock, extra delivery journeys, and often new packaging too. Strong, correctly-sized mailing bags reduce damage and therefore reduce waste overall.

For brands that want a softer eco look, pairing parcels with paper bags for retail presentation can work well, while mailing bags stay the best choice for posting because they protect against moisture.

Mailing bags are made from recyclable LDPE film and can be reused multiple times. Many councils and supermarkets now accept soft plastics; you can check current UK guidance on sites such as Recycle Now.

How to Reduce Returns and “Damaged Parcel” Complaints

Most damage complaints come from three avoidable issues:

• Wrong size bag (overfilled, stretched, split seams)
• Poor seal (flap not pressed down fully)
• Incorrect packaging choice (fragile items in mailing bags)

A strong packing routine cuts complaints quickly. If you want to upgrade your standard dispatch, start by standardising one size for most orders (12×16 is the common choice for UK clothing sellers) and keep a bigger option ready for bulkier parcels (13×19).

Coloured vs Grey Mailing Bags: Which Is Best for Packing?

For packing quality, colour is not the deciding factor — size and strength are. Many sellers use grey for everyday shipping because it looks neutral and professional. Others use colour for brand recognition and unboxing appeal, using colour collections like pink and purple for boutique parcels, or blue for a clean, corporate feel.

If you want the simplest approach: use grey mailing bags as your main dispatch packaging, then use colour for special parcels, gifts and premium orders.

Internal Link Boost: The “Go-To” Packing Setup for UK Sellers

If you want one simple setup that works for most UK eCommerce shipping, here is a reliable starting point:

• Mailing bags: Choose your everyday bags from the Mailing Bags collection
• Grey bags: Build your core dispatch around Grey Mailing Bags
• Reinforcement: Keep Packaging Tape available for heavy items
• Fragile orders: Use Cardboard Boxes for rigid products

This single setup covers most clothing, accessory and soft-goods shipping needs in the UK, while keeping your packing process consistent.

Packing Checklist: The Step-by-Step Method That Prevents Mistakes

Use this checklist every time you pack an order. It takes seconds and prevents the most common dispatch errors.

1. Select the correct bag size (do not stretch the film).
2. Fold and place the item flat, keeping weight away from the flap area.
3. Remove excess air and keep the parcel neat.
4. Seal straight and press firmly across the full strip.
5. Apply label flat and clear (no folds, no seams).
6. Check postcode and house number before dispatch.

Mistakes to Avoid When Packing with Mailing Bags

• Overfilling bags – causes splits and weak seals.
• Sealing at an angle – reduces adhesive contact.
• Label on seams – causes scanning problems and label lift.
• Sharp corners unprotected – rubs through film.
• Using a mailing bag for a fragile item – often ends in damage claims.

If you fix just these five issues, you’ll normally see fewer complaints and smoother dispatch within weeks.

Useful Downloads

• Mr Bags Mailing Bags Size Guide (PDF)
• Mr Bags Bulk Order Form (PDF)
• Royal Mail Size & Weight Guide

Our Trust & Service Guarantee

We aim to deliver a fast, simple and reliable packaging service for every UK business. All orders are shipped with same-day dispatch (cut-off applies) and fast nationwide delivery. Our customers rate us 5★ on Trustpilot for quality, service and value. Bulk and trade support is available for larger businesses—simply contact our team for tailored help.

Final Summary: How to Pack Parcels Properly in 2026

Good packing is not complicated — it’s consistent. Choose the right mailing bag size, keep items flat, seal firmly, and place labels correctly. Use mailing bags for soft goods and boxes for fragile items. If you want a simple, dependable dispatch setup, start with the Mailing Bags range, build around Grey Mailing Bags, and keep Packaging Tape and Cardboard Boxes ready for heavier or fragile orders. This approach protects your parcels, reduces returns and keeps customers confident in 2026.