In climbing, a carabiner is a piece of gear that is used as a connection point. This could be connecting a belay device to your harness, the rope to an anchor, or connecting a piece of protection (like a quickdraw, cam, or nut) to the rope as you climb.

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Each of these are carabiners that are certified and used for climbing:

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Pictured above you'll see carabiners of all shapes and sizes, some locking and some non-locking. Some also have additional features like a belay keeper.

All carabiners for climbing have a gate that opens and closes, and some of them have a gate that locks. Their shapes and sizes can vary, but they’re all some sort of stretched oval-ish looking shape that roughly fit in an adults hand. (Technically there are official shapes: Offset D, HMS/Pear, and Oval’s that are used in different settings.)

The biggest and most important difference for where/when carabiners are used, is decided by one factor: if they’re locking or not. Locking carabiners are used when the carabiner will not open frequently and/or needs to stay locked for safety. Non-locking carabiners are used in areas that do not have much movement and/or have limited possibility of opening accidentally and/or it is ok if the carabiner opens accidentally. (For exact details, read our Locking vs Non-Locking post.)

Indoors – Where carabiners are used

Climbing indoors you’ll primarily see carabiners used in two ways.

1. While belaying. The carabiner will connect the belay device to the belayers harness. In this case it will always be a locking carabiner.

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Note: Locking carabiners come in many different styles. There are some with a screw gate, where you have to manually screw closed, or screw open, the screw mechanism to lock and unlock the gate. There are also gates that are auto-locking. Auto-locking carabiners mean that when the gate is closed, the carabiner will automatically be locked (though you should still test it, to make sure the locking mechanism is working properly). Read more about screw vs autolocking carabiners here and learn more about the different auto-locking styles in this post.

2. While lead climbing. In this case non-locking carabiners are connected to a quickdraw, or fixed permadraw. Quickdraws and permadraws both have a non-locking carabiner where the lead climber connects their rope. The photo below shows a permadraw, where one end is “permanently” connected via a quicklink to the wall, and the carabiner end has a rope clipped.

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Here’s another view, where the lead climber has clipped the rope into a carabiner. The carabiner is also the lower half of the the permadraw. (Note: Climbers often say “quickdraw” even if/when they are referring to a permadraw.)

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3. At anchors, while lead climbing. At the top of the climb, the lead climber will clip into anchors (which may be a locking or non-locking carabiner) to be lowered. Since these carabiners will not likely move much, it is ok for them to be non-locking. Some gyms have opted to reduce risk as much as possible, and will have a type of locking carabiner at the anchors.

4. Routesetting. Routesetters will use carabiners in many different ways to hold things, to assist in hauling, or while positioning themselves to be able to add (or remove) holds to a wall.

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5. Optionally Hanging Gear. Some climbers use non-locking carabiners to hold their chalk-bag on their harness. This was never the intended use of the webbing on the back of harnesses, but is possible to use. A more helpful method of hanging the chalkbag is to use a waistbelt – this means the chalkbag will be higher, for easier access.

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Outdoors – Where carabiners are used

In addition to belaying and lead climbing mentioned above, outdoor climbers also will use carabiners in many different type of anchor situations and will need carabiners to hold gear to their harness.

The montage below shows carabiners being used at anchors while multi-pitch trad climbing (a style of climbing that uses the most gear).

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The photo below shows carabiners being used as anchors at the top of a sport crag.

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An outdoor trad climber will often use a lot of carabiners for racking gear – holding many different types of gear (cams, nuts, tricams, hexes, nut tool, etc) on the harness while trad climbing.

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The photo below shows a climber building a trad anchor, key to all the connection points are carabiners.

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The photo below shows an anchor while big wall climbing – which is a very long multi-pitch trad climb. In big wall climbing carabiners are used for hauling gear, aid climbing, to connect anchors, to haul bags, to tie climbers to anchors, to support portaledges, and connect other gear.

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Carabiners are also used for rigging and positioning while doing photography. Sometimes this can look similar to the way that routesetters use carabiners indoors.

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Things to Know About Carabiners

There are literally hundreds of carabiners to choose from. So how do you decide what to buy or recommend? It all depends on what you want to do and where you want to do it. To understand all the carabiner decision points & nuances that could lead to a personal preference, here are the areas to research further:

Note: The biggest difference between carabiners is whether they are locking or non-locking. After that choice is made, most carabiners can complete most jobs at least 80% of the time without frustration. All the reading and posts below are for the most curious climbers, who want to be able to completely understand their gear and have it work well for them 99% of the time. 

In case you missed the links above:

Locking vs non-locking – when/where they’re used – the most important carabiner decision

Screw vs auto-locking carabiners – manual closure or automatic pros/cons

Auto-locking carabiners compared – all the different styles of auto-lockers compared

Carabiner shape – the shape can make belaying or clipping easier, for example

Racking carabiners – the carabiners that hold gear on your harness

Additional links:

Understanding carabiner strength – this is more of an fyi, showcasing how you never have to worry if the carabiner is strong enough, as long as it’s an officially rated carabiner

Keylock vs non-keylock – talking about the nose of the carabiner to help prevent the nose from hooking up accidentally

Gate Openings – how to make it easier to clip/unclip the carabiner or things into the carabiner

And a few more related topics to inspect and maintain your carabiners:

How to Clean and Maintain – so you don’t have to retire them!

When to retire your carabiners – likely you won’t do this very often – but see what makes the difference!

How to recycle and upcycle old carabiners – more upcycling than recycling, unfortunately