Best Large Letter Box Mailers of 2026

Jordan Akhtar Avatar
Jordan Akhtar
Last Updated: 10 Feb 2026

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Large Letter Box Mailers are a great solution for businesses and individuals who need to send items through the post without incurring the higher costs of sending a parcel. These mailers are designed to fit through a standard letterbox, making them a convenient and cost-effective option for sending items such as books, DVDs, and small gifts. Made from high-quality materials, they offer protection for your items during transit and are available in a range of sizes to suit your needs. Whether you're sending a single item or a larger quantity, Large Letter Box Mailers are an excellent choice that will help you save money and get your items to their destination safely.

At a Glance: Our Top Picks

100 Large Letter Boxes by MEG4TEC Cover #TOP 1
100 Large Letter Boxes by MEG4TEC
ftb score rating icon 9.8
AKAR Large Letter Postal Boxes Pack of 50 Cover #TOP 2
AKAR Large Letter Postal Boxes Pack of 50
ftb score rating icon 9.7
50 Pack PIP Box Shipping Mailers Cover #TOP 3
50 Pack PIP Box Shipping Mailers
ftb score rating icon 9.5

Top 9 Large Letter Box Mailers

100 Large Letter Boxes by MEG4TEC

OTH1_SRMRMBC5_100_P1
Brown
100 Large Letter Boxes by MEG4TEC Cover
100 x C5 A5 PIP Box Shipping Mail Postal Large Letter Boxes - Size: 235x165x22mm Sold by MEG4TEC

The MEG4TEC Large Letter Boxes are designed to meet your mailing needs with convenience and reliability. Each box has an external size of 235mm x 165mm x 22mm, making it perfect for large letter shipping. With an internal size of 225mm x 160mm x 20mm, you can easily fit various items securely inside. Weighing only 35g, these boxes are lightweight, which can help reduce postage costs. Made from sturdy 1mm thick single wall cardboard, they provide excellent protection for your contents during transit.

What We Like
Lightweight design for cost efficiency
Sturdy cardboard for protection
Generous internal space
Ideal for large letter shipping
#TOP 2

AKAR Large Letter Postal Boxes Pack of 50

AKPIPA4*50
Brown
Pack of 50 Boxes
AKAR Large Letter Postal Boxes Pack of 50 Cover
A4/C4 || 320x230x20mm || Large Letter Postal Boxes - A4 & C4 Sizes - Pack of 50

The AKAR Postal Boxes are ideal for sending fragile items securely, thanks to their robust single-wall corrugated cardboard construction. These large letter postal boxes are lightweight yet sturdy, ensuring your items are well-protected during transit. With a convenient locking tab, you can easily secure your package, making them perfect for gifts or retail items. Plus, they are stackable and quick to assemble, saving you time and effort when preparing your shipments.

What We Like
Durable, recyclable cardboard
Easy to assemble
Secure locking tab
Lightweight and sturdy
Versatile for various uses
#TOP 3

50 Pack PIP Box Shipping Mailers

Parcel Pack
50xC5
Brown
50 Pack PIP Box Shipping Mailers Cover
Generic 50 x C5 A5 PIP Box Shipping Mail Postal Large Letter Boxes - Size: 235x165x22mm Sold by MEG4TEC

The PIP Box Mailers come in a convenient pack of 50, perfect for your shipping needs. With external dimensions of 235mm x 165mm x 22mm, they qualify as large letter boxes, making them ideal for mailing various items. The sturdy 1mm thick single wall cardboard ensures your packages are well-protected during transit. Additionally, these mailers are quick and easy to assemble, allowing you to save time on packing. You can seal them securely with clear or brown tape made from recycled material, contributing to an eco-friendly packaging solution.

What We Like
Strong cardboard construction
Easy to assemble
Large letter size
Pack of 50 units
Eco-friendly sealing options
#TOP 4

Large Letter Cardboard Shipping Boxes by SR Mailing

LGELETBOXC4005
Brown
Large Letter Cardboard Shipping Boxes by SR Mailing Cover
50X C4 A4 Size Box Large Letter Strong Cardboard Shipping Mailing Postal Pip, LGELETBOXC4005

The SR Mailing C4 Postal Boxes are designed for your shipping needs. Made from robust 1.2mm thick single wall cardboard, they ensure your items are well-protected during transit. Each box is delivered flat-packed and securely wrapped, making storage easy and convenient. You will appreciate how quick and easy they are to assemble, allowing you to prepare your parcels in no time. With a size qualifying for large letter postage, these boxes are perfect for sending documents and other flat items efficiently.

What We Like
Durable 1.2mm thick cardboard
Delivered flat-packed for convenience
Quick and easy assembly
Large letter postage qualified

AKAR C6 Large Letter Postal Boxes - Pack of 50

PIP-C6**
Brown
AKAR C6 Large Letter Postal Boxes - Pack of 50 Cover
AKAR C6 A6 Size 112 x 163 x 20 mm Large Letter PIP Boxes for Royal Mail - Pack of 50

The AKAR C6 Postal Boxes are ideal for shipping fragile items safely. Made from durable, lightweight corrugated cardboard, these boxes ensure your items remain secure during transit. They feature a convenient locking tab for easy closure, allowing you to send gifts or stationery without worry. With a flatpack design, these boxes are easy to assemble, saving you time and effort when preparing your parcels. Recyclable and strong, they provide excellent protection compared to standard mailers.

What We Like
Durable and lightweight
Easy to assemble
Secure locking tab
100% recyclable
Protects fragile items
#TOP 6

AKAR C5 A5 Large Letter Postal Boxes

PIP-C5**
Brown
Pack of 50 Boxes
AKAR C5 A5 Large Letter Postal Boxes Cover
AKAR Corrugated Manila Large Letter Postal Box C5 A5 PIP Boxes Royal Mail

The AKAR Postal Boxes are ideal for shipping fragile items securely. Made from durable single-wall corrugated cardboard, they ensure your belongings remain safe during transit. Their lightweight design makes them easy to handle, while the locking tab allows for secure closure. These versatile boxes are perfect for gifts, stationery, or e-commerce shipping, providing a practical solution for all your mailing needs.

What We Like
Durable and recyclable material
Easy to assemble and use
Secure locking mechanism
Suitable for various items
Flat packed for convenient storage
#TOP 7

Triplast C6 Large Letter Postal Box White

PIPC6
White
Pack of 50
Triplast C6 Large Letter Postal Box White Cover
Triplast C6 160 x 110 x 20 mm White PIP Cardboard Large Letter Postal Box for Royal Mail (Pack of 50)

The Triplast C6 Postal Box is designed with an easy-to-assemble FEFCO 0427 style, featuring fold-over ends and secure ear lock lids, which helps you pack quickly and safely. It fits Royal Mail's 'Large Letter' size, allowing you to save on postage costs when sending smaller items. With internal dimensions of 160x110x20mm, the box offers ample space for phones, accessories, or other small goods, while its robust 125 WK/T single wall cardboard construction ensures reliable protection during transit.

What We Like
Easy to assemble design
Royal Mail size compliant
Durable single wall cardboard
Secure ear lock lids
#TOP 8

150 Large Letter Box Shipping Mailers

OTH1_SRMRMBC5_150_P1
Brown
150 Large Letter Box Shipping Mailers Cover
150 x C5 A5 PIP Box Shipping Mail Postal Large Letter Boxes - Size: 235x165x22mm Sold by MEG4TEC

The MEG4TEC Mail Postal Boxes are designed for efficient shipping with their external dimensions of 235mm x 165mm x 22mm, making them suitable for large letter qualifications. The internal size of 225mm x 160mm x 20mm provides ample space for your items while keeping them protected. Each box weighs just 35g, ensuring that your postage costs remain low. Made from sturdy 1mm thick single wall cardboard, these boxes offer excellent durability, giving you peace of mind that your items will arrive safely at their destination.

What We Like
Lightweight design
Durable cardboard material
Ample internal space
Large letter qualified
#TOP 9

AKAR White Large Letter C5 Postal Boxes Pack

AKPIPWA5-PK100
White
Pack of 100
AKAR White Large Letter C5 Postal Boxes Pack Cover
AKAR White A5/C5 Large Letter Box - 218x159x20mm - Postal Pip Box for Royal Mail [Pack of 100]

The AKAR C5 Postal Boxes are large letter cardboard boxes designed to help you ship items securely. Made from durable, single-wall corrugated cardboard, they are lightweight yet sturdy, keeping your items safe during transit. These boxes are ideal for sending fragile goods or gifts and can be easily decorated with ribbons for a personal touch. The secure locking tab ensures your package stays closed without extra tape or glue, making them quick and simple to assemble and use for mailing, postage, or delivery at home or work.

What We Like
Durable corrugated cardboard
Lightweight but sturdy
Secure locking tab
Easy to assemble and fold
100% recyclable and UK made
Buying Guide Image

Frequently Asked Questions (FAQs)

1. Can I post box large letter?

The maximum Parcel size allowed into our new Postboxes is 44cm x 35cm x 16cm. Any Royal Mail Special Delivery Guaranteed items, Royal Mail International Tracked items, and any Royal Mail Tracked Returns without a barcode on the label must be posted in a Post Office branch and cannot be dropped off at a Parcel Postbox.

2. What size is a large letter box?

The Royal Mail large letter size was introduced in 2006 as part of the new Pricing in Proportion (PiP) policy. A large letter's size can be no larger than 353 x 250 x 25mm (a normal letter can be only up to 240 x 165 x 5mm) with a maximum weight of 750g.

Editor's Notes

During our large letter box mailer research, we found 250 large letter box mailer products and shortlisted 9 quality products. We collected and analyzed 43,990 customer reviews through our big data system to write the large letter box mailers list. We found that most customers choose large letter box mailers with an average price of £11.08.

The large letter box mailers are available for purchase. We have researched hundreds of brands and picked the top brands of large letter box mailers, including AKAR, Parcel Pack, SR Mailing, Triplast.

Written by
Jordan Akhtar Avatar

Jordan Akthar owns one stationery store in Bradford, and another in Derby. He started with a corner bookshop, and now the rest is history. He is often found in his stores taking count of inventories of books and stationery. Jordan also likes to write, and this drove his passion for writing articles on stationery maintenance. He owns a blog, where in his free time, he would write DIY tips on how you can recycle and refine your stationeries.