This is something that comes up regularly enough to be discussed here.
We don't provide canyoning shoes on our tours (or footwear on our ridge climbs).
The reason for this is that, to some extent, they are a non-essential item.
We can't take you into the canyon without a helmet or harness (or wetsuit for most of our canyons, for most of the year).
Canyoning specific shoes are expensive and relatively short lived. For our canyons, an old pair of trainers will suffice. We do provide 5mm neoprene socks to wear inside - keeping your feet comfortable and warm.
Our guides have run our canyons in sandals* and trainers - trust us - footwear is not the main reason your footing is unsteady if you join us for your first time canyoning. It is a slippery environment if you don't know where to step (which is why we teach you how to move and put you in a 5mm wetsuit for that extra padding).
If we were to provide canyoning footwear, it puts up the cost quite considerably.
If we wanted to cover that cost, we'd have to put up our prices or increase our group sizes and run more tours. Either way, it is a compromise that works out as a net negative for you - in our estimation.
We want to keep tours as affordable as possible.
We do not want to run bigger scale tours and run them more frequently. The quality of the tour isn't the same and the environment pays a much higher price too (things just get trampled and ruined).
As the first canyoning company, here in Korea, we also want to set a precedent for low impact tours as well.
It might be worth mentioning that I stopped wearing canyoning specific boots about two years ago. I now take my old approach shoes that have had their sticky soles worn out on South Korea's rocky mountain trails and ridges. I would not let you enter our canyons in footwear that I thought was setting you up for trouble.
*we insist that you wear footwear with close toes on our toes. If our guides bloody their tour in the canyon they've no-one to blame but themselves - they know better. We don't allow you to take even minor risks unless we're absolutely 100% certain that you 100% understand the implications of said decision.