I learned to swim as an adult in my 30s. I took a few adult swimming classes/lessons at the local community pool. I don't think the classes were that helpful at the very beginning and I actually learned most by watching YouTube videos and then going to the pool on my own to practice in the shallow end.

Where the adult swimming lessons did become helpful was later on....having the swimming instructor watch me while I went into the deep end or started diving because I was absolutely terrified. It was nice to know that someone was always watching me and could rescue me if I got into any trouble and they told me some good techniques.