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Large Letter Postal Boxes

The Royal Mail ‘Large Letter’ boxes are an excellent, economical way to send your items provided they fit within the 353mm x 250mm x 25mm size allocation, and are below 750g in weight. Our ‘Large Letter Postal Boxes’ are an excellent way to ensure your parcels stay within the required size guidelines. They arrive flat-packed for simple storage and take seconds to assemble. Their size will not only save on shipping, but will ensure the items arrive in a sturdy, professional way!

Showing all 10 results

DL PIP Royal Mail Large Letter Boxes

C4 PIP Royal Mail Large Letter Postal Boxes – Brown (320mm x 230mm x 20mm)

£3.95 Ex VAT £4.74 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

320mm x 230mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
C4 PIP Royal Mail Large Letter Postal Boxes - White

C4 PIP Royal Mail Large Letter Postal Boxes – White (320mm x 230mm x 20mm)

£3.95 Ex VAT £4.74 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

320mm x 230mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
DL PIP Royal Mail Large Letter Boxes

C5 PIP Royal Mail Large Letter Postal Boxes – Brown (218mm x 159mm x 20mm)

£4.45 Ex VAT £5.34 Inc VAT Out of Stock – Due back on Thursday 22nd January 2026
L x W x H

218mm x 159mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
Royal Mail Large Letter Postal Boxes (PIP) - White

C5 PIP Royal Mail Large Letter Postal Boxes – White (218mm x 159mm x 20mm)

£4.45 Ex VAT £5.34 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

218mm x 159mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
DL PIP Royal Mail Large Letter Boxes

C6 PIP Royal Mail Large Letter Postal Boxes – Brown (112mm x 163mm x 20mm)

£3.50 Ex VAT £4.20 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

112mm x 163mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
Royal Mail Large Letter Boxes (PIP) - White Mini

C6 PIP Royal Mail Large Letter Postal Boxes – White (112mm x 163mm x 20mm)

£3.50 Ex VAT £4.20 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

112mm x 163mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
DL PIP Royal Mail Large Letter Boxes

DL PIP Royal Mail Large Letter Postal Boxes – Brown (217mm x 108mm x 20mm)

£3.95 Ex VAT £4.74 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

217mm x 108mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
Royal Mail Large Letter Boxes (PIP) - White Mini

DL PIP Royal Mail Large Letter Postal Boxes – White (217mm x 108mm x 20mm)

£4.20 Ex VAT £5.04 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

217mm x 108mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
DL PIP Royal Mail Large Letter Boxes

MINI PIP Royal Mail Large Letter Postal Boxes – Brown (101mm x 101mm x 20mm)

£2.95 Ex VAT £3.54 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

101mm x 101mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page
Royal Mail Large Letter Boxes (PIP) - White Mini

MINI PIP Royal Mail Large Letter Postal Boxes – White (101mm x 101mm x 20mm)

£3.45 Ex VAT £4.14 Inc VAT Order by 3pm, delivered Next Working Day
L x W x H

101mm x 101mm x 20mm
Box Type

Royal Mail Large Letter Boxes
Select options This product has multiple variants. The options may be chosen on the product page

FAQs

Our large letter postal boxes are specifically designed to meet Royal Mail’s size restrictions, offering a smart and reliable solution for slimline shipping. They provide a professional appearance, maximise usable internal space, and give you the confidence that your parcel will meet postage requirements without incurring extra costs. Made from durable, high-quality materials, they’re ideal for businesses looking to maintain consistency and efficiency in their packing process.

All of our large letter postal boxes are designed to stay within Royal Mail’s maximum size limit of 353mm x 250mm x 25mm. We offer a selection of box formats, including C4, C5, DL and Mini PIP styles, so you can choose the best fit for your items while keeping postage costs down. Every box in the range meets Royal Mail’s guidelines for large letter sizing, making them ideal for shipping documents, clothing, accessories and other low-profile products through the post.

Yes - if you're ordering in larger volumes, we can supply custom-printed or bespoke-sized large letter boxes to suit your brand or packaging operation. Please get in touch with our team to discuss minimum order quantities and lead times.

Yes - all of our large letter postal boxes are made from recyclable cardboard and manufactured using responsibly sourced materials. They're a plastic-free packaging option that can be recycled with standard paper and board waste, making them ideal for businesses looking to reduce environmental impact.

Yes. According to Royal Mail's guidelines, large letter parcels must not exceed 750g in weight. This applies alongside the maximum size of 353mm x 250mm x 25mm. If your item is heavier or bulkier, it may need to be sent as a small parcel instead.

Send Postal Orders Efficiently with our Large Letter Postal Boxes

Our large letter postal boxes are the perfect item to help you send large letters through Royal Mail. Dispatch orders with confidence knowing that your parcels will be the perfect size to travel every time, streamlining any personal or business postage processes.

Eco-Friendly Solutions for Shipping Products

Tired of using plastic or polyurethane bags to dispatch your products? Our range of cardboard postal packaging is the ideal solution to ensure your parcel looks great and arrives safely. 

Like all our cardboard products, our large letter postal boxes are 100% recyclable and biodegradable, making them the perfect option for high-volume shipping. 

Save Time and Money With Our Large Letter Postal Boxes

Our large letter postal boxes are available to purchase in bulk and come with free UK shipping on orders over £50 (+VAT), saving you time and money on shipping costs.