| Lock types | Screwgate, twist-lock, magnetic |
| Used for | Belay, anchor, rappel — critical links |
| Vs. | Non-locking (used on quickdraws) |
| Difficulty | Beginner (requires instruction) |
A locking carabiner is a metal connector whose gate can be locked shut so it cannot open accidentally. Climbers use it for critical connections — attaching a belay device, clipping into an anchor, or rappelling — where an open gate could be catastrophic. Locks are either manual (screw) or automatic.
How it differs from a regular carabiner
A standard carabiner has a sprung gate that can be bumped open. A locking model adds a sleeve or mechanism that secures the gate, trading a little speed and weight for security at the connections that matter most.
What to look for
Match the shape to the job — a pear-shaped (HMS) locker for belaying, a D-shape for anchors. Consider the lock type (screwgate vs. auto-lock), gate size, and weight. A clove hitch for personal anchoring should always be tied on a locker.
Common mistakes & safety
The classic errors are forgetting to lock the gate and loading the carabiner across its gate rather than along the spine. Build the habit of locking and giving the gate a squeeze-check before weighting it. This article is educational and not a substitute for hands-on instruction from a qualified climbing instructor.
Frequently asked questions
When should you use a locking carabiner?
Use one at any single, critical connection where an accidental gate opening would be dangerous: the belay device, the master point of an anchor, a rappel setup, or a personal tether. Non-locking carabiners are reserved for redundant connections like quickdraws.
Are screwgate or auto-locking carabiners better?
Screwgates are simple, light, and let you check the lock by sight, but they can be left unlocked. Auto-locking gates close themselves, reducing user error, but are bulkier and can jam with grit. Many climbers carry both for different jobs.
What does it mean to load a carabiner across the gate?
It means the load pulls on the weaker gate side rather than the strong spine, which can dramatically reduce strength. A locking carabiner should always be oriented so force runs along its long axis, with the gate closed and locked.
Sources
- Connector technical notice — Petzl
- Belaying and anchoring — American Alpine Club