Security bags are used to transport or store sensitive items with visible tamper evidence. They are designed to make interference obvious during handling and transit, supporting reconciliation, audit trails and chain-of-custody procedures where required. They’re commonly used for confidential documents, cash handling, evidence workflows and healthcare logistics. This guide explains the main types of security bags, typical applications, and what to consider and specify when it comes to security and traceability features.
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What are security bags?
Security bags are an umbrella term covering several formats—single-use envelopes/mailers, reusable PVC pouches and higher-capacity security sacks—used to control movement of sensitive items. The right format depends on whether the journey is one-way or closed-loop, the size/weight of contents, and the level of identification needed for your workflow.
Quick selector: which security bag do you need?
Most buying decisions come down to three factors: what you are transporting, whether the journey is one-way or closed-loop, and the level of traceability required.
Single-use security envelopes and tamper-evident mailers are typically chosen for post, courier and external transfers. Reusable security pouches are usually chosen for repeat routes and internal logistics, typically secured each trip using a disposable tamper-evident seal. For higher capacity/bulk movements, consider security sacks.
Evidence workflows may require additional identification and process controls. For diagnostic samples, UN3373 packaging follows a specific pack format. For airport and duty free liquids, STEB bags use ICAO-style markings and origin coding to support transfer checks.
Single-use vs reusable: quick comparison
Single-use tamper-evident bags are designed to be sealed once and removed from use, making them suitable for one-way transfers and deposits. Reusable security pouches and sacks are designed for repeat handling in closed-loop routes and are typically secured each trip using a disposable tamper-evident seal. Many organisations use both: single-use externally and reusable internally where durability and route control matter.
Single-use: tamper-evident bags | Reusable: reusable security bags
Types of security bags and when to use them
Single-use security envelopes and tamper-evident mailers
Single-use security envelopes (often called deposit envelopes or tamper-evident mailers) are designed for one-way movements such as post, courier and external transfers. They are commonly used for confidential documents, cash deposits, key handling, small valuables and secure despatch where the receiving party needs clear evidence of opening. They are available in either clear (see-through) or opaque white film, depending on whether the contents of the sealed bag should be visible or not.
Single-use tamper-evident security bags are commonly specified where you need both visible evidence of opening and simple traceability through a process, particularly where items are leaving your organisation's control. Features depend on the specific bag, but include Level 1 or Level 4 security closures, reinforced side welds with microprints, sequential numbering, barcode IDs and tear-off receipt formats for handover records.
STEB bags (duty free security bags)
STEB bags (Security Tamper-Evident Bags) are specialist tamper-evident bags used in airports and duty free retail to package liquids and other goods for onward travel. ICAO-style STEB bags use recognisable red/green markings with origin coding (State/airline code and manufacturer identifier) to support transfer checks and screening controls. View options here: STEB bags (duty free security bags).
Reusable security pouches and carriers (PVC)
Reusable PVC security pouches and carriers are designed for repeat use in closed-loop processes such as internal logistics, controlled distribution and regular collections/deliveries. They are typically secured each trip using a disposable tamper-evident seal, supporting route control and repeat handling.
Security sacks (higher capacity / heavier duty)
Security sacks are used where capacity and durability are priorities—for example bulk movements, consolidations or higher-volume routes. They are commonly secured using a tamper-evident seal through eyelets or locking points and can support identification and route control in the same way as other security bag formats.
Evidence and chain-of-custody formats
Evidence workflows typically prioritise identification and repeatable handover procedures. Formats may include write-on panels, unique IDs (numbering/barcodes) and tamper-evident closures designed to make opening or interference clearly visible. The best option depends on your process: how items are logged, stored and handed over.
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Common applications (cash, documents, healthcare and evidence)
Confidential documents and secure mail
For secure post, courier and internal transfers of documents, single-use security envelopes and mailers are commonly specified. Choose a format that suits the document size and contents (flat vs gusseted), and consider unique IDs if you need an audit trail or proof of dispatch/receipt.
Cash handling and valuables
For one-way deposits and external transfers, single-use deposit envelopes/tamper-evident mailers are common. For repeat routes (closed loop), reusable PVC pouches are often selected for durability and route control. Identification features (numbering/barcodes/receipts) can support reconciliation at each handover.
Evidence handling
Evidence processes typically require consistent identification and logging. Bags may be specified with write-on areas, unique IDs, and tamper-evident closures that show clear signs of opening. Where chain-of-custody is required, build the bag specification around your handover and recording steps.
Healthcare logistics and diagnostic samples
Healthcare workflows vary widely. For secure movement of documents, personal property or non-regulated items, standard tamper-evident formats may be suitable. For diagnostic samples transported as Category B biological substances, UN3373 packaging follows a specific pack format and typically requires leakproof 95kPa bags, absorbent materials and compliant outer packaging.
View UN3373 packaging components here: UN3373 Category B (P650) secondary packaging.
Single-use vs reusable: how to choose
The simplest way to choose is to start with the journey type:
- One-way / external transfer: usually single-use security envelopes or tamper-evident mailers.
- Closed-loop / repeat route: usually reusable PVC pouches or sacks, secured each trip with a disposable tamper-evident seal.
Then refine your choice by considering contents (documents vs bulky items), how many handovers occur, whether you need a receipt, and whether you need scanning/ID at multiple points. For duty free liquids and airport transfers, use ICAO-style STEB bags with the required markings and origin coding.
Tamper evidence and traceability: what to specify
Security bags are designed to provide visible evidence of attempted interference. In practice, they work best when combined with good process controls (for example counts, handover records and tracked delivery services where appropriate). When specifying a bag, consider:
- Tamper-evident closure type (Level 1 or Level 4 security closures, or numbered security seals for reusable formats)
- Unique identification (sequential numbering and/or barcode formats)
- Handover support (tear-off receipts or write-on panels where needed)
- Format and capacity (flat vs gusseted; envelope vs pouch vs sack)
- Material requirements (including recycled content or reusable closed-loop objectives)
Where to buy security bags online
When buying online, focus on the format that matches your workflow and the level of traceability you need. For many buyers, the key decision is whether stock sizes are sufficient or whether controlled distribution and routing require custom print.
- Browse all types: security bags
- Single-use envelopes and mailers: tamper-evident bags
- Reusable pouches and sacks: reusable security bags
- Duty free / airport transfers: STEB bags (duty free security bags)
- UN3373 packaging components: UN3373 Category B (P650) secondary packaging
- Custom sizes/print/ID formats: custom single-trip security bags
Frequently asked questions
Next steps
If you know your application, start here and select the format that matches your workflow: