There are a few basic things you need to remember when choosing diving boots. First of all, you should select the thickness that is right for your needs. Just like your wetsuit, most dive booties are made of neoprene and range in thickness from 2mm to 8mm. Most divers prefer their boots and wetsuit to be of the same thickness. Heavy boots, such as 5mm and thicker are great for colder water conditions, while thinner ones work well in warmer water.
Wetsuit Boots also come in different sole thickness. In particular, there are boots with the soft sole, medium sole, and hard sole. Soft sole is mainly used for boat diving or beach entries in the areas with little to no debris. It’s best to go for boots with medium sole if you will be diving in the areas with some small hazards. Hard sole booties are designed for areas where you would have to step on rocks or dead corals. In general, heavy soles provide more protection, while thinner soles offer more flexibility.
As for the cut of the boots, the rule of thumb is to go for the low cut or mid-height, if you are primarily diving in warm water and pick high cut boots in case you will do some cold water dives.
With that said, purchasing diving boots is a good idea if you are using open heel fins, as most boots simply won’t fit under the full foot fin. If you want to wear something for additional warmth and protection against blisters with your full foot fins, neoprene or lycra socks will be a good solution.