Zen Backpack Zipper Locks






Backpack Zipper Locks aka Travel Locks, Luggage Locks, Mini Padlocks, Suitcase Locks, Backpack Locks, Bag Lock,  Carry On Lock, TSA Locks, Password Locks, Combination Locks


Backpack Zippers

Zipper Maintenance/Repair

Zipper Security

Zipper Locks



There are many locks to choose from out there. 


Keyed Locks

The really small luggage locks with stamped keys found in Asia or that come with cheep luggage can often be opened by a novice with a paperclip.  These are lightweight and if you loose your keys, they are not too hard to remove from your pack.



A good quality keyed mini-lock is easy to find.  They can be light weight, provide minimal bulk and work well with lockable zipper sliders.  When purchasing keyed locks, you many want to purchase several lock which are keyed alike so that you only need to pack a single key (and one spare). 


It's easy to find a small lock suitable for locking lockable zipper sliders


It is easy to find a mini keyed lock with a short shackle which allows for less zipper travel when used on single looped lockable zipper sliders.  Compared to locks with combinations dials, most combo locks have longer shackles, which allow for greater zipper separation.


Padlock Sliders with Single Locking Tab

Padlock Sliders with Single Locking Tab

Zipper separation with long shackled lock

A sleeve could be added to the shackle to allow for a tight fit



Combination Locks aka Combo Locks, Dial Locks and Password Locks

Combination locks - these are great for those who know they are likely to loose their keys on any giving trip or for those who want the luxury of going keyless.  Unfortunately, combo locks suitable for backpack zippers tend to be a bit bulkier and heavier than keyed locks intended for travel.



Many combination locks can be opened by applying a little downward traction to the lock and spinning the combination keys until the correct combination is selected.  Although it may seem like finding the correct combination may seem like selecting the correct lottery number, nimble fingers can sequentially spin the dial of a 3 digit lock and open it in less than a minute.  Most of the low security mini locks for zippers allow for this and can be checked by locking your lock, applying downward traction and slowly spinning past your code to see if it opens.  Some higher quality locks prevent you from doing this and may be preferred for packs that will be left unattended (e.g. in you room, stored on top of busses with local travelers, etc.). 



A high quality 4 combo lock may take hours to decode and are better suited for left behind baggage, shared room locks and locker locks than 3 combo locks.


Many combination locks seem "large" in comparison to the zippers they are locked to


Some combination locks may have shackles that are just too long to provide desirable closure of your zipper.  You can easily shorten the usable length of your shackle by creating a spacer or epoxying on a backstop to create a snug fit for the zipper.



Cable Locks

Cable locks allow you to wrap around objects such as bag handles and tie down loops.  Some are long enough to lock multiple zippers and even wrap around table legs and other fixed objects to secure you backpack when stationary. 


Mini cable locks can be threaded through the back of most backpack zippers where the zipper pulls are attached

This allows you to lock most reasonably sized zippers without modification


Some are small enough that they can easily pass through the back of a regular backpack zipper so that you can lock up just about any backpack with double zipper sliders without modification.  The downside to cable locks is they can often be defeated with simple hand tools which easily fit in a thief's pocket.  Cable locks can also allow for a LOT of play between sliders, depending on how they are used.


A Cable lock can allow for a lot of play between zipper slider

It would be easy to pull zipper apart and fit hand in this bag.


Depending on your setup, you may be able to use a single cable lock to secure more than one set of zippers and/or secure your bag to something else.


Built in Cable lock securing 3 sets of zippers in place



Airport Security (TSA) Locks

With today's security measures in many international airports and those within the US and Europe, you may need a specially approved TSA (US) and HMRC (UK) lock if you want to lock your gear and avoid loosing your lock.  These TSA locks are also keyed so that security screeners at airports and other security checkpoints can open your lock without damaging them.  This unfortunately leaves them vulnerable to many of the same people you would like to protect your bags against in the first place, as well as anyone with a set of easy to find/make special keys.  To deter pilfering of your bags at the airport, it may we worth your while to add a zip tie to your zippers in addition to your TSA lock.  This may deter the occasional corrupt screener and let you know if someone has been in your bag if you receive your bag without your zip tie.



Safe Skies and Travel Sentry icons


Locks that can be opened with a set of TSA keys should be easily identifiable by security agents so that they are not cut with bolt cutters.  There are two major companies (Safe Skies and Travel Sentry) that make TSA approved locks and can be identified by there logos on the face of the lock.  Combination locks should have a key hole for a TSA key in addition to the combo.  Some of these locks have an indicator that marks the lock after it has been opened by a TSA key, to let the owner know if someone has been in their bags.



Unfortunately, TSA approved combination locks tend to be on the larger side and overkill for the small zippers on your backpack but


TSA double cylinder design


Using TSA approved locks may be necessary if you would like to secure checked in bags and would like to avoid replacing broken locks on a regular basis.  The problem is that by design, TSA combination locks have two lock cylinders, one for the combination dials and one for the TSA key.  This double cylinder lock design requires more real estate and adds more weight to the lock, making most a bit heavy and large for backpack zippers.  


If you are not using TSA locks primarily to secure baggage for flight or don't mind risking the occasional broken lock, then you can epoxy or superglue the keyed portion of the TSA lock.  This will prevent someone with a TSA key set (or compatible jiggler set or in some cases - embarrassingly simple tools) from unlocking your lock.  But since most thieves don't carry around a set of these keys or know how to pick locks, this is generally not necessary.


ClipLok uses a sacrificial and replaceable shackle


ClipLok uses a different approach where the shackle is expected to be cut.  The lock also allows security agents the ability to relock the cut lock and the cut shackle can be later replaced.  Of course you will likely need to replace the entire lock after it is thrown in the trash by security agents, unless you are lucky and they throw it back in your bag.

US Patent  8327674

US Patent  20110079054

US Patent  20120234062

US Patent  20120011909



Makeshift Locks

Pacsafe bag with snapping hooks for securing zipper pulls

S-Biner holding zipper pulls together

Simple clasps can be cute too


Simple clasps, snap-links, carabineers, snapping S link hooks, quick links, key rings, safety pins and the like can slow down grab and run pickpockets and are easier to undo than keyed and combo locks.  These may not be good options for bags that will be stationary and unattended but are generally sufficient enough to deter thieves that don't want to fool around with these devices while a bag is on your back.  Security can be further increased by using links with a threaded lock which further slow down unclasping and by hiding these links under a pouch or flap.


Locking links make great little "locks"


Threaded link locks make for great zipper locks since they take a little bit of fiddling to undo.  When these are partially hidden under a flap, they become rather difficult to undo by someone not familiar with your setup.  And once you are familiar with this setup, you can undo and redo the locks without looking.  Use string and a clove hitch to secure these to your pack so that you don't lose them.


Zip ties make great one time use lock

Seals (PrivaSeal ) are a step up from zip ties


Zip Ties are great for one time use only, such as for checking in luggage at an airport.  This allows you to easily secure your baggage and lets you know if someone was in your bag.  A small bag of zip ties is easy to pack away and all you need is a nail clipper to access your bags later.


Locking Stitch Markers are available in plastic and metal as well as in many designs


corporatetravelsafety.com  zipper-locks-p-1465 S-Biner

corporatetravelsafety.com  lock-purse-security-zipper-lock-clip-p-81 Zip-R-Lock Purse Security - Zipper Lock Clip (Model #1030)

backpackingdiplomacy.com  how-to-avoid-pickpockets-the-psychology-of-a-thief safety pin

ladylighttravel.com  casual-theft-and-the-rule-of-three Safety Pin Lock

survival.outdoorlife.com  paracord-bracelets-10-practical-uses-other-fashion


GooglePatents  US20080229554

GooglePatents  US7464569

GooglePatents  US7200901

GooglePatents  US2223347

GooglePatents  US2297657 snap can be used to hold zipper shut

GooglePatents  US2845670 can be used with button anchor



Lock Quality, Durability and Security

The quality of locks varies tremendously.  Some can be easily defeated with crude pick or simple tricks, while others are reasonably effective at denying entry considering their size.


The best way to assess the strength of security is to understand all the ways a lock's security can be defeated.  This site doesn't want to become an information site for defeating security measures, so this section will focus on basic quality of locks.  It is important to note that the weakest point of security is its weakest link.  And if you are just locking up a zipper, then the zipper or fabric around it becomes the weak link.  If you are on the other hand securing a slashproof bag with a reinforced closure, the quality of your lock may actually make a difference.


You should pack one good padlock for lockers and such

This one is overkill and is too heavy to carry around all the time

This one is also too heavy for a zipper and can cause damage to the zipper slider or zipper


Basic Considerations

  Poor Moderate Good  
Visual Appearance Looks like junk but was a great buy Looks nice Looks solid  
Shackle Construction Hollow Clasp - easily twisted or cut

Plastic - can be twist broken or cut

Cable - can be cut Solid steel - bigger is better as long as it fits  
Body Construction Plastic - can be crushed, deformed and sometimes twisted

Cast aluminum or pot metal

Stamped steel body Solid machined metal

Laminated - stacked hardened steel

TSA Lock TSA locks -

Well known how to defeat

not for locker, room or left behind baggage

TSA Combo Lock with Epoxy in keyhole Non-TSA Lock  
Lock Type Low Quality Combo - defeated with minimal skill High Quality Combo - defeated with time Keyed - requires special skill and tools  
Lock Mechanism Shackle snaps shut - prone to shim attack   Turn key or combo to lock  
Key Design Flat or stamped - defeat with paper clip and no skill 3 toothed milled key (16-20 differs) 4+ tooth milled key (200+ differs)  
Combination Dials Plastic - will wear down over time if abused   Metal dials  
# of Dials 2 - 100 Combinations

Easy to defeat

3- 1000 Combinations -

1 minute to crack some

40 minutes for others

4- 10,000 Combinations

Hours to crack quality lock




Twisting the shackle with fingers will cause plastic Block to easily twist and fail

Aerostich Derlin Lock - light weight, but easy to pick or break


How much lock do you need? That depends on several factors:




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