Avail free shipping on minimum orders of £75
Profile
  • Register
  • Log in
  • Shopping basket (0)
Buy In Uk
Menu
  • School & Educational Supplies
  • Office Supplies
  • Office Paper Products
  • Art & Craft Supplies
  • Envelopes & Mailing Supplies
Menu
  • School & Educational Supplies
  • Office Supplies
  • Office Paper Products
  • Art & Craft Supplies
  • Envelopes & Mailing Supplies
(0)
Search
Shopping basket
You have no items in your shopping basket.
  • Home /
  • Envelopes & Mailing Supplies /
  • 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes
Picture of 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes
Picture of 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes
Picture of 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes
Picture of 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes
Picture of 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes
Picture of 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes
Picture of 50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes

Accepted Payment Methods

50 x C5 White Self Seal Security Envelopes | Fully Opaque, Self Sealing & Printer Safe Mailing Paper Envelopes

Best In Quality | Top Selling Item

307 review(s) | Add your review
£10.99 ex. VAT
£5.99 ex. VAT
Want to get it delivered Tomorrow?
Order within 13 Hrs 36 Mins via Next day signed for or Special delivery
ColourWhite
Closure typeSelf-Seal
MaterialPaper
Number of items50

About This Item:

  • Pack of 50 – ideal for home, office, and business mailing needs.
  • C5 size (229x164mm) – fits A5 documents or A4 folded in half.
  • High-security inner tint – keeps contents confidential and private.
  • Self-sealing closure – easy and secure adhesive strip for hassle-free sealing.
  • Durable 90 GSM paper – strong and resistant to tearing.
  • Printer-friendly – compatible with inkjet and laser printers.
You may also like
Picture of Ballpoint Red Pen, Pack of 12 Ballpoint Pens, Smooth Writing Action - Medium Point Nib (1.0mm) Red multipack, Ball point pens

Ballpoint Red Pen, Pack of 12 Ballpoint Pens, Smooth Writing Action - Medium Point Nib (1.0mm) Red multipack, Ball point pens

ColourRed
Ink colourRed
Age range (description)Adult
MaterialPlastic
Point typefine,medium point
Special featureQuick Drying
Unit count12.0 count

About This Item:

  • Effortless Writing – Smooth, skip-free ink flow for clean handwriting.
  • Quick-Drying & Smudge-Free – Keeps notes and documents neat.
  • Ergonomic Comfort Grip – Designed for long writing sessions without fatigue.
  • Medium 1.0mm Point – Perfect for bold, precise writing.
  • Multipurpose Use – Ideal for students, teachers, professionals, and home use.
  • Value Pack of 12 – Great for daily writing, note-taking, and marking.
£16.99 ex. VAT £8.99 ex. VAT
In stock
Picture of Math Set Kids Protractor School Supplies GCSE Geometry Sets Small Clear Transparent See Through Exam Pencil Case for Boys Teenagers Girls and Students

Math Set Kids Protractor School Supplies GCSE Geometry Sets Small Clear Transparent See Through Exam Pencil Case for Boys Teenagers Girls and Students

MaterialClear PVC (Transparent)
Set Includes10-Piece Math Set
Case TypeZip-up Transparent Pencil Case
Dimensions21 x 12.5 x 1 cm
Weight90 g
Ideal ForStudents, teachers, professionals

About This Item:

  • 10-Piece Complete Geometry Set – Includes ruler, protractor, set squares, pens & more.
  • Transparent & Exam-Friendly – Clear case allows quick visibility of stationery.
  • Durable & Lightweight – High-quality PVC case, easy to clean & carry.
  • Perfect for Students & Professionals – Ideal for school, teachers, architects & engineers.
  • Compact & Portable – Fits easily into backpacks & school desks.
£9.99 ex. VAT £4.99 ex. VAT
In stock
Picture of Study and Revision Planner Pad for Students - 52 thick A4 sheets for school, college and university revision and exams - Academic Planner

Study and Revision Planner Pad for Students - 52 thick A4 sheets for school, college and university revision and exams - Academic Planner

Material100gsm Premium Paper
SizeA4 (30.6 x 21 cm)
Number of Sheets52 (1 per week for a year)
Sheet FormatCustomisable Weekly Planner
PortabilityLightweight & Easy to Carry

About This Item:

  • 52 A4 Tear-Off Sheets – Plan a whole year’s study schedule with ease.
  • Customisable Weekly Layout – Colour-code and organise your tasks.
  • Daily Task Sections – Track subjects, assignments, and progress.
  • To-Do List Section – Manage personal and academic responsibilities.
  • Premium 100gsm Paper – Thick, high-quality sheets for smooth writing.
  • Perfect for Students – Ideal for school, college, and university learners.
£19.99 ex. VAT £9.99 ex. VAT
In stock
Picture of 800PCS Punny Teacher Sticker for Student, Motivational Reward Stickers for Kids Classroom, Must Have Essentials for Teachers Elementary

800PCS Punny Teacher Sticker for Student, Motivational Reward Stickers for Kids Classroom, Must Have Essentials for Teachers Elementary

MaterialPaper PVC Vinyl
Size per Sheet9.4 x 6.2 inches
Sticker Size1 to 2 inches per sticker
WaterproofYes
AdhesionStrong, leaves no residue

About This Item:

  • 800 High-Quality Stickers – 40 sheets with 20 unique punny designs.
  • Fun & Motivational – Encourages kids with cute and colorful animal-themed stickers.
  • Perfect for Teachers & Parents – Use as rewards for homework, good behavior, and achievements.
  • Waterproof & Durable – Made of glossy, high-quality PVC vinyl for long-lasting use.
  • Versatile Uses – Great for classroom charts, notebooks, water bottles, laptops, and more.
£18.99 ex. VAT £9.99 ex. VAT
In stock
Picture of 6pcs/set Kawaii Cartoon Cat Gel Pen for Girl Gift Stationery Cute Writing Handles Pens Nice Office School Supplies

6pcs/set Kawaii Cartoon Cat Gel Pen for Girl Gift Stationery Cute Writing Handles Pens Nice Office School Supplies

Colour6 Pieces
Ink colourBlack
MaterialPlastic
Point typeExtra Fine
Special featurePocket clip

About This Item:

  • Adorable Kawaii Design – Features cute cat-themed details for a fun stationery upgrade.
  • Smooth & Precise Writing – 0.5mm extra fine tip with quick-drying black gel ink.
  • Comfortable Grip – Designed for effortless and neat handwriting.
  • Multi-Purpose Use – Ideal for school, office, journaling, and sketching.
  • Perfect Gift Idea – Great for girls, students, and cat lovers.
£9.99 ex. VAT £3.87 ex. VAT
In stock
Picture of 17 Pcs Stationary Sets, Maths Sets For Secondary School, Secondary School Stationery Set, Back To School Stationery Ruler Set

17 Pcs Stationary Sets, Maths Sets For Secondary School, Secondary School Stationery Set, Back To School Stationery Ruler Set

MaterialsPremium quality, durable materials
Dimensions24 x 15.9 x 4 cm
Weight330 g
Use CaseSchool, Office, Exam Preparation
DesignCompact, portable, and organized

About This Item:

  • 17 Essential Pieces: Complete set with 1 pencil case, 4 rulers, 1 notebook, 3 highlighters, 4 pencils, and more.
  • Durable and High Quality: Crafted with premium materials for long-lasting use.
  • All-in-One Solution: Perfect for school, exams, or office use.
  • Compact Design: Easy to store and carry for students on the go.
  • Perfect for Any Student: Ideal for secondary school students and anyone in need of reliable stationery for studying or exams.
£20.99 ex. VAT £10.99 ex. VAT
In stock
Picture of 10 Pcs Animal Finger Puppets Toys Hand Puppets Toys Mini Plush Figures Toy Assortment for Boys & Girls Finger Puppets

10 Pcs Animal Finger Puppets Toys Hand Puppets Toys Mini Plush Figures Toy Assortment for Boys & Girls Finger Puppets

MaterialPlush
ThemeChristmas, Animal
Number of pieces10

About This Item in Bullet Points:

  • 10 Animal Finger Puppets: Includes 10 different animals like elephants, rabbits, and more.
  • Soft & Safe: Made from high-quality plush material, safe for young children.
  • Educational Fun: Helps children learn about animals, improve motor skills, and boost imagination.
  • Great Gift Idea: Perfect for birthdays, Christmas, and other special occasions.
  • Portable & Easy to Use: Small size, perfect for on-the-go fun or bath time play.
£12.99 ex. VAT £5.99 ex. VAT
In stock
  • Overview
  • Reviews
  • Contact Us

50-Pack C5 White Self-Seal Security Envelopes – Fully Opaque & Printer-Safe

Introduction:

Ensure secure and hassle-free mailing with our 50-pack C5 white self-seal security envelopes. Designed for home, office, and commercial use, these 90 GSM envelopes feature a high-security inner tint to keep contents confidential. With a self-sealing closure and printer compatibility, they offer convenience and reliability for everyday mailing needs.

Key Benefits:

  • Perfect C5 size – fits A5 documents or A4 papers folded in half.
  • Enhanced security – blue inner pattern ensures complete confidentiality.
  • Self-sealing adhesive – no tape or licking required, just peel and press.
  • Printer safe – compatible with most inkjet and laser printers.
  • Eco-friendly & recyclable – made from sustainably sourced PEFC-certified paper.

Why Choose C5 White Self-Seal Security Envelopes?

  • Comprehensive 50-pack – great for bulk mailing and office supplies.
  • Durable 90 GSM paper – strong enough to prevent tearing and damage.
  • Tamper-proof design – security-tinted interior protects sensitive information.
  • Professional & versatile – suitable for both business and personal use.
  • Made in the UK – premium quality and reliable craftsmanship.

Applications:

  • Sending invoices, statements, and business letters.
  • Mailing brochures, catalogues, and periodicals.
  • Storing and organizing confidential documents.
  • Suitable for home, office, and commercial use.
  • Ideal for postal services and business correspondence.

Specifications:

FeatureDetails
MaterialPaper
Paper Weight90 GSM
Envelope SizeC5 (229x164mm)
Closure TypeSelf-Seal Adhesive Strip
Security TintYes
Printer CompatibilityInkjet & Laser Printers
ColorWhite
QuantityPack of 50
Eco-FriendlyRecyclable & PEFC Certified

FAQs:

Q: Can these envelopes fit A4 documents?
A: Yes, they fit A4 paper folded in half or A5-sized documents perfectly.

Q: Are these envelopes secure for mailing sensitive documents?
A: Absolutely! The blue security tint inside prevents contents from being seen.

Q: Is the self-seal closure strong enough for secure mailing?
A: Yes, the adhesive strip creates a firm and tamper-proof seal.

Q: Can I print directly on these envelopes?
A: Yes, they are compatible with most inkjet and laser printers.

Q: Are these envelopes eco-friendly?
A: Yes, they are recyclable and made from PEFC-certified sustainably sourced paper.

  • Only registered users can write reviews
*
*
*
*
*

50-Pack C5 White Self-Seal Security Envelopes – Fully Opaque & Printer-Safe

Introduction:

Ensure secure and hassle-free mailing with our 50-pack C5 white self-seal security envelopes. Designed for home, office, and commercial use, these 90 GSM envelopes feature a high-security inner tint to keep contents confidential. With a self-sealing closure and printer compatibility, they offer convenience and reliability for everyday mailing needs.

Key Benefits:

  • Perfect C5 size – fits A5 documents or A4 papers folded in half.
  • Enhanced security – blue inner pattern ensures complete confidentiality.
  • Self-sealing adhesive – no tape or licking required, just peel and press.
  • Printer safe – compatible with most inkjet and laser printers.
  • Eco-friendly & recyclable – made from sustainably sourced PEFC-certified paper.

Why Choose C5 White Self-Seal Security Envelopes?

  • Comprehensive 50-pack – great for bulk mailing and office supplies.
  • Durable 90 GSM paper – strong enough to prevent tearing and damage.
  • Tamper-proof design – security-tinted interior protects sensitive information.
  • Professional & versatile – suitable for both business and personal use.
  • Made in the UK – premium quality and reliable craftsmanship.

Applications:

  • Sending invoices, statements, and business letters.
  • Mailing brochures, catalogues, and periodicals.
  • Storing and organizing confidential documents.
  • Suitable for home, office, and commercial use.
  • Ideal for postal services and business correspondence.

Specifications:

FeatureDetails
MaterialPaper
Paper Weight90 GSM
Envelope SizeC5 (229x164mm)
Closure TypeSelf-Seal Adhesive Strip
Security TintYes
Printer CompatibilityInkjet & Laser Printers
ColorWhite
QuantityPack of 50
Eco-FriendlyRecyclable & PEFC Certified

FAQs:

Q: Can these envelopes fit A4 documents?
A: Yes, they fit A4 paper folded in half or A5-sized documents perfectly.

Q: Are these envelopes secure for mailing sensitive documents?
A: Absolutely! The blue security tint inside prevents contents from being seen.

Q: Is the self-seal closure strong enough for secure mailing?
A: Yes, the adhesive strip creates a firm and tamper-proof seal.

Q: Can I print directly on these envelopes?
A: Yes, they are compatible with most inkjet and laser printers.

Q: Are these envelopes eco-friendly?
A: Yes, they are recyclable and made from PEFC-certified sustainably sourced paper.

Product tags
  • self-seal envelopes (7)
  • ,
  • white envelopes (3)
  • ,
  • mailing envelopes (3)
  • ,
  • office envelopes (2)
  • ,
  • business envelopes (2)
  • ,
  • c5 envelopes (1)
  • ,
  • security envelopes (1)
  • ,
  • printer-safe envelopes (1)
  • ,
  • recyclable envelopes (2)
  • ,
  • 90 gsm envelopes (1)
  • ,
  • tamper-proof envelopes (1)
Related Products
Picture of Padded Envelopes  A5  Padded Bubble Envelopes Bags Postal Wrap Envelope

Padded Envelopes A5 Padded Bubble Envelopes Bags Postal Wrap Envelope

Colour:20pk White
Closure type:Self-Seal
Material:Plastic
Number of items:20

About this item:

  • Easy to use with excellent label adhesion. Write on easily with any pen, no need for anything special !
  • Pack your items fast with these peel and seal bags. Peel off the protective strip to reveal the adhesion and press down to seal envelope
  • Our padded envelopes are perfect for delivery and logistics for small accessories like cosmetics, jewelry, gadgets etc.
  • Lightweight yet superb padding for all goods, provided excellent protection against crushing
£29.99 ex. VAT From £11.19 ex. VAT
In stock
Picture of Premium Cash Gift Envelopes (Pack of 25) - Assorted Colours Self-Adhesive

Premium Cash Gift Envelopes (Pack of 25) - Assorted Colours Self-Adhesive

Colour:Gold on White Red Blue Grey Black
Closure type:Self-Seal
Occasion:Baptism, Christmas, Wedding, Birthday, Shagun
Material:Cardstock

About this item:

  • ELEGANT - Fancy GOLD CONFETTI design that is neutral but elegant on 5 colours - making it suitable for all occassions - birthdays - anniversaries - weddings- christenings - diwali - bandi shor divas - gurpurab - easter - new year and more!
  • EASY TO WRITE ON! - unlike other fancy envelopes these have been coated in a way that still allows for easy writing, so you can personalise it easily as you wish
  • SELF ADHESIVE! Finally a fancy envelope that you can seal easily without ruining the style. Simply peel the paper off the double sided tape, and close to seal.
  • DESIGNED TO GIFT MONEY - made to measure for UK currency. Can still fit credit card sized cards if you are gifting a gift card or vouchers.
  • ALL ONE DESIGN - this pack is all one design on multiple colours - unlike other items on the market, you know exactly what to expect when you order from us!
  • HIGH QUALITY - sturdy card, with a neat finish and no regional smells.
£34.99 ex. VAT From £12.99 ex. VAT
In stock
Picture of 125 Mixed Grey Plastic Mailing Mail Post Postage Bags Assorted Sizes Packaging Poly Postal mailers

125 Mixed Grey Plastic Mailing Mail Post Postage Bags Assorted Sizes Packaging Poly Postal mailers

MaterialPlastic
ColourGrey
Unit count125 count
Style‎Poly

About this item:

  • Pack of 125 durable plastic mailing bags in assorted sizes for varied packaging needs

  • Grey opaque design ensures privacy and professional presentation

  • Water-resistant & tear-proof material for reliable shipping

  • Self-seal adhesive strip for quick and secure closure

  • Perfect for eCommerce, retail, home, and office postage

  • Lightweight and cost-effective for reducing postage costs

  •  Suitable for clothing, documents, accessories, and soft items

£16.99 ex. VAT £8.99 ex. VAT
In stock
Picture of 125 Assorted Mixed Pink Mailing Poly Postal Self Seal Bags

125 Assorted Mixed Pink Mailing Poly Postal Self Seal Bags

ColourPink
Closure typeSelf-Seal
MaterialPlastic
Number of items125

About this item:

  • These Opaque Mailing bags incorporate a permanent self-seal closure and are made from an opaque 60 micron film. Our posting bags have a self-adhesive strong closure. These air sealed postage bags are water and dirt resistant and made to secure the inside and outside.
  • Safe and Secure Package Bags:- These plastic mailers have a sticky strip for easy closure. Once sealed, these bags are very hard to open allowing your items to arrive safely without risk of opening or tampering.
  • Small to Large Mailing bags 4.5 x 7 Inch / 6 x 9 Inch / 9 x 12 Inch / 10 x 14 Inch / 12 X 16 INCH. Parcel bags for posting Mailing Packaging and more
  • Plastic envelopes for posting:- Small to Large postage bags are very light weight and sturdy. You can use its full size or put something smaller inside and wrap the excess before sealing.
  • These Plastic Postage Bags can be used for any Courier or sealed Airtight storage Purpose, you will get these bags in five different sizes, ideal for packing items of all types, shapes and sizes. The self-seal lip makes the parcel air tight and water resistant for personal and business use.
£14.99 ex. VAT £7.99 ex. VAT
In stock
Picture of 60 Mixed Size Self-Seal Mailer Bags | Tamper-Proof Plastic Packaging for Mailing, Postage, Shipping & Delivery | Grey (4 Sizes | Small to Large | 15 each)

60 Mixed Size Self-Seal Mailer Bags | Tamper-Proof Plastic Packaging for Mailing, Postage, Shipping & Delivery | Grey (4 Sizes | Small to Large | 15 each)

MaterialPlastic
Product dimensions10L x 10W millimetres
ColourGrey
Item weight0.46 Kilograms

About This Item:

  • 4 Sizes: 6x9 inches, 9x12 inches, 10x14 inches, and 12x16 inches.
  • Self-Adhesive Closure – Peel-and-seal for easy packing.
  • Waterproof & Oilproof – Protects contents from moisture and damage.
  • Durable – Crafted from high-quality polythene material.
  • Versatile – Great for clothes, electronics, decor, and more.
£6.99 ex. VAT £3.99 ex. VAT
In stock
Picture of  110 x 220 mm 90 gsm Self Seal Wallet Envelopes (13882/100 PR) White - 100 Count ( Pack of 1)

110 x 220 mm 90 gsm Self Seal Wallet Envelopes (13882/100 PR) White - 100 Count ( Pack of 1)

ColourWhite
Closure typeSelf-Seal
OccasionOffice
MaterialPaper

About This Item:

  • Self-Seal Closure – Easy to seal without glue or water.
  • Security Opaque – Ensures privacy and confidentiality.
  • 90 gsm Paper – Durable, sturdy, and premium-quality paper.
  • Ideal for Office Use – Perfect for mailing letters, invoices, and more.
  • Pack of 100 – Plenty of envelopes for all your mailing needs.
£12.99 ex. VAT £6.99 ex. VAT
In stock
Picture of  A3 A4 A5 A6 Gold/White Bubble Padded Envelopes Peal & Seal, Ideal for Mailing Goods | Packaging Bags, Gold, A6(100mm x 165mm), Pack of 10

A3 A4 A5 A6 Gold/White Bubble Padded Envelopes Peal & Seal, Ideal for Mailing Goods | Packaging Bags, Gold, A6(100mm x 165mm), Pack of 10

ColourGold
Closure typeSelf-Seal
OccasionMailing Goods
MaterialPaper

About This Item:

  • Premium Gold Design – Elegant and professional appearance for shipments.
  • Bubble Padded Protection – Keeps items safe from damage.
  • Peel & Seal Closure – Quick, easy, and secure sealing.
  • Lightweight & Durable – Reduces shipping costs while ensuring protection.
  • Pack of 10 – Ideal for businesses, offices, and personal use.
£8.99 ex. VAT £4.99 ex. VAT
In stock
Secure Payments
30 Days Money Back Guaranteed
100% Satisfaction Guaranteed
Easy Returns
Newsletter
Wait...
Find us also on

Please contact the Customer Services for returning address.
For all question about orders or general enquires please contact us:
BUYINUK
Office 4077wri 58 Peregrine Road, Hainault
Ilford, Essex IG6 3SZ, United Kingdom
sales@buyinuk.co.uk
+44 747 720 4634

Information
  • Shipping Policy
  • Billing Terms & Conditions
  • Returns & Refunds
  • Privacy policy
  • Terms & Condition
  • About us
  • Contact us
Customer service
  • Search
  • Blog
  • Compare products list
  • FAQ
My account
  • My account
  • Orders
  • Addresses
  • Shopping basket
  • Apply for vendor account
Copyright © 2025 Buy In Uk. All rights reserved.