So what sort of protection am I referring to when you go Canyoneering?
The physical kind that keeps you safe, covers your head, protects your gear from additional damage. Additionally, thermal protection from cold water along with sunscreen for direct-sun conditions. Finally, knee, elbow and hand protection from canyon abrasion, especially found in the more narrow slot canyons.
Hopefully you can tell by now, that is the answer just "all depends". Some of those answers depend on the specific canyon(s), depends if it recently rained or not in the area, and time of year that you are going.
Helmet - absolute must, required for every technical canyon
Wetsuit - absolute must in water (sometimes a drysuit is even preferrable in the summer in alpine canyons)
Drysuit - absolute must in winter canyoneering
Knee protection - when in "skinny" canyons and high-stemming is required. Generally, they are not a bad idea to have them stored away in your canyoneering backpack.
Elbow protection - when in "skinny" canyons and high-stemming is required. Generally, they are not a bad idea to have them stored away in your canyoneering backpack.
Hand protection - in other words, gloves. The gloves that have been dipped in rubber and are less than $10 work best for overall hand protection.
Sun-screen - very important when out in the hot desert sun. Keeps you from getting burns on your neck and your face and can prevent skin-cancer.
A Helmet is absolutely vital in Canyoneering. Don't be caught without one.
(See Module 18 - Canyoneering Gear for more info).
If you plan on doing any serious or long-term Canyoneering, than you will need to buy yourself a wetsuit. There are numerous sizes, colors, lengths, thickness, and types.
As you have seen, Canyoneering typically contains some amount of water in a canyon. Remember, canyons are the sewer systems of Mother Earth. Water can be trapped in a canyon for months! Some of those canyons depths may only see the sunlight for an hour a day or less. In other words you can count on that water being cold!
How a wetsuit works is by trapping a very thin later of water between your bare body and the neoprene. Your body heat will warm up the layer keeping you "warm". The form-fitting wetsuits work best as you want it skin-tight to maximize your warmth. The looser it fits, the colder you will be.
Types of wetsuits: Full, Short or "Shortie", Farmer-John
Thickness (in milimeter): 2 mm to 7 mm. (the thicker it is the more warmer you will be)
Colors: you name it, they have it.
Brand: no particular brand is preferred.
Typically, canyoneers wear full wetsuits that are in the 3 mm size. I have been told by multiple women, that 5 mm wetsuits is especially preferred for a woman as they run colder than men.
I own multiple wetsuits as you can see above, but it usually just depend on the canyon on which one I bring. If there is a lot of water, I bring my more durable one. If there is just one or two swimmers, I'll bring the shortie and go back into dry clothes right after the swimming portions. I have even heard of people using two wetsuits at the same time for additional warmth. This would work but be VERY bulky and hard to manuever with, unless it was like a 1 or 2 mm size wetsuit. But in that case, I would just turn to a DRYSUIT (see below for more info).
Additional tidbits about wetsuits: 1) When you get back from your canyon trips, please rinse them out throughly with clean water before you store them. This will help alleviate the smell that they can trap with them. There are neoprene cleaners on the market that do help with the cleaning and smell if normal tap water doesn't do the trick. 2) Neoprenes sometimes have a marijuana-like smell to them and I would advise keeping them in the garage and not in the house. My older brother when he would come to visit would often be like "are you guys doing marijuana here?" "uh, what? No! Well, it smells just like it". Apparently we got use to the smell after a year of them being in the basement, but after that and smelling them deeply in. It did indeed smelled just like it! So we moved them out to the garage and the smell is completely gone from the basement now.
How a drysuit differs from a wetsuit, is that a drysuit actually keeps you dry (go figure). The only exceptions are your head, hands, and sometimes feet (as some suits do not contain a built-in bootie).
Most drysuit manufactures use a "gasket" that is essentially a seal around your neck, wrists, and ankles that prevent all water from coming into the suit therefore keeping you dry on 95% of your body. I have worn just a t-shirt and running long-pants underneath in water that was below freezing and was quite comfortable.
While I wasn't wet, I could feel the cold. And once you were out of the water, you felt totally fine again.
I would recommend drysuits in the coldest water or for individuals who have zero-cold tolerance but want to do canyoneering.
They do come at a price as they can vary from $700 to $2000. I own three of them currently and my favorite one by far is made by Level Six and is called the "Emperor". It has built-in booties, extremely comfortable, compacts down better than my other drysuits, and has a great neon color to it (mines Lime Green). They retail for $900 and if I was to suggest one, this is the brand and model I would buy again. My Kokatat is an older version (year 2010) and was bulky, and the gaskets irritated my skin. (Perhaps they have improved since then?)