An ice plunge tub is the vessel you sit in for cold immersion, and it is worth separating from the cooling that keeps it cold, because the two are bought separately more often than people expect. The tub decides how you sit, how much water you need, how fast it warms back up and where it can stand. Get that right and the cooling question becomes simple; get it wrong and no chiller rescues it.
Inflatable, stock tank and insulated shell
An inflatable tub is the cheapest entry and packs away, at the cost of insulation, durability and a comfortable seated position. A galvanised stock tank is the classic improvised option: cheap, tough and completely uninsulated, so it needs a lot of ice and warms quickly. An insulated shell, usually a molded or timber-clad tub with a fitted lid, holds temperature far longer and is what makes daily use practical, whether you are using ice or a chiller. The insulation is the single feature that most changes the running experience.
How you sit in it
Cold immersion is uncomfortable by design, and the shape of the tub decides how much of that discomfort is the cold and how much is your back. Some shells are built to sit upright with knees bent, some to recline with legs extended, and a tall user in a short tub will find shoulders or knees permanently out of the water. Depth matters as much as length: submersion to the shoulders is what most people are after, and a shallow tub will not give it whatever its footprint suggests.
Water, siting and upkeep
Filled, even a modest tub is heavy enough to matter on a deck and will sink into soft ground, so most end up on pavers or a slab. You need a way to fill it and, more importantly, somewhere for the water to go when you empty it. Without filtration the water needs changing often, because a tub used repeatedly by people is a tub that needs sanitation; with a chiller and filtration, one fill can last weeks. Decide which of those you want before choosing the tub, because retrofitting is harder than buying right.
Questions people ask about ice plunge tub
Can I just use a stock tank?
Many people do and it works. It is cheap and durable but completely uninsulated, so it needs far more ice and warms up quickly, which makes daily use expensive in ice or slow to get cold.
How much water does an ice plunge tub hold?
It varies widely by model, and the number matters mainly because it sets how much ice or cooling capacity you need. Deeper tubs that submerge you to the shoulders naturally hold more.
Do I need a lid?
If you want the water to stay cold between sessions, yes. A fitted insulated lid is the cheapest single improvement to how long a tub holds temperature, and it keeps debris out of the water.