Crampon in the context of Mountaineering boot

Ice climbing is a climbing discipline that involves ascending routes consisting entirely of frozen water. To ascend, the ice climber uses specialist equipment, particularly double ice axes (or the more modern ice tools) and rigid crampons. To protect the route, the ice climber uses steel ice screws that require skill to employ safely and rely on the ice holding firm in any fall. Ice climbing routes can vary significantly by type, and include seasonally frozen waterfalls, high permanently frozen alpine couloirs, and large hanging icicles.

Ice climbing originated as a subdiscipline of alpine climbing, where sections of scalable ice are encountered alongside segments instead necessitating rock or mixed climbing. Ice climbing arose as an independent sport in the 1970s. Modern ice climbing includes a difficulty grading system peaking at WI6 to WI7, as ice tends to hang vertically at its most severe. WI7 is very rare and usually attributed to overhanging ice with serious risk issues (i.e. unstable ice, little protection, and a risk of death). Mixed climbing has pushed the technical difficulty of ice climbing routes by crossing bare rock overhangs and roofs. This can entail dry-tooling, the use of ice tools on bare rock.

Free solo climbing (or free soloing) is a form of rock climbing where the climber (or free soloist) climbs on technical terrain without ropes or any form of protective equipment — they are allowed to use climbing shoes and climbing chalk (or ice tools and crampons if ice climbing). Free soloing is the most dangerous form of climbing, and, unlike bouldering, free soloists climb at heights where any fall can be fatal. Though many climbers have free soloed routes with technical grades that they are very comfortable on, only a tiny group free solo regularly, and at technical grades closer to the limit of their abilities.

The international profiles of some climbers have been significantly increased by their free soloing activities, such as Alex Honnold, Alex Huber, Alain Robert and John Bachar, but others question the ethics of this, and whether the risks that they are undertaking should be encouraged and commercially rewarded. While "free solo" was originally a term in climbing slang, after the popularity of the 2018 Oscar-winning film Free Solo, Merriam-Webster added the word to their English dictionary in September 2019.

An ice tool is a specialized elaboration of the modern ice axe, and often described broadly as an ice axe or technical axe, used in modern ice climbing and mixed climbing. Modern ice climbers usually use them in pairs when ascending an ice climbing route, and thus in some circumstances such as top-rope-anchored climbs, a pair may be shared among two or more people, where only one of them at a time is climbing. In contrast a classical "ice axe" is used by one person for the hours or days a party is traveling across snow or glacier. In communities where it is common to refer to an "ice tool" simply as an "ice axe", classic "ice axes" are often referred to as "traveling axes", "walking axes", or "general mountaineering axes" to distinguish them from "tools".

In climbing of vertical ice, two tools are needed in order for the climber (supported by cramponed feet) to use each tool in turn in maintaining balance with the body's center of mass nearly straight above the toes, while repositioning the other tool to a higher level, before raising the body weight with the legs and thereby setting the stage for repeating the process.

Mixed climbing is an ice climbing discipline used on climbing routes that do not have enough ice to be regular ice climbs, but are also not dry enough to be regular rock climbs. To ascend the route, the mixed-climber uses normal ice-climbing equipment throughout (e.g. double ice tools or ice axes in their hands, and crampons on their feet), but to protect the route, they use both ice and rock equipment. Mixed climbing varies from routes with sections of thick layers of ice interspersed with sections of bare rock, to routes that are mostly rock but which are "iced-up" in a thin layer of ice and/or snow.

While alpinists have used mixed climbing techniques for decades on alpine routes (most north-facing alpine routes are iced or snow-covered), mixed climbing as a standalone sport came to wider prominence with Jeff Lowe's ascent of the partially bolted Octopussy (WI6, M8 R) in 1994. Mixed climbing also led to the sport of dry-tooling, which is mixed climbing on routes that are completely free of all ice or snow. The equipment used — the lengths of ice tools and the use of heel spurs and ice axe leashes — has become more regulated to avoid concerns of being more like aid climbing than free climbing.

Dry-tooling (or drytooling) is a form of mixed climbing that is performed on bare, ice-free, and snow-free, climbing routes. As with mixed-climbing, the dry-tooling climber uses a pair of ice tools and wears crampons to ascend the route. They will use normal rock climbing equipment for their protection on the route; many modern dry-tooling routes are now fully bolted as with sport climbing rock-climbing routes. Many indoor ice climbing competitions are held on bare non-iced surfaces and thus effectively dry-tooling events.

Dry-tooling as a standalone activity developed from the mid-1990s as the standards of mixed-climbing rose dramatically, and the most difficult part of the new extreme M-graded mixed-climbing routes was often the dry-tooling component (e.g. a bare rock roof or a severe rock overhang). Some of the most extreme mixed-climbing routes will also quote a dry-tooling D-grade alongside the M-grade to signify whether there was any ice encountered (i.e. Iron Man in Switzerland is graded M14+/D14+).