Correct gym and swimming pool attire query

[condor]

Have joined a new ( still being built) health club with gym, swimming pool and spa that I'm interested in making use of. It's due to open late March and I want to know what the suitable attire would be for swimming pool and spa - with my first attempts at gym work being on the stationary bicycles.
I'm guessing a swimming cap is essential ? and full black/navy blue swimsuit? Do people wear bath robes to the pool/spa?
Possibly a track suit top and bottoms for my first attempts at gym work?

[condor]

I haven't been to a gym/ purpose built swimming pool for serious swimmers or spa. Don't think it's that absurd an idea to ask for advice.
I'm a woman and don't have any suitable attire at all. I see I'll do better asking at the health club nearer to it's opening time - just thought I might get a heads up here on what is normal gym/pool/spa gear.
I don't have a pair of flip flops, so thanks, that was a good suggestion.

[condor]

Thanks Great info been given in the last few posts

[condor]

Thanks for the update
I'll buy myself a blue one piece swimming costume...I do like the idea of a skirt, but that might be a bit too vintage.
My current swimsuit is a one piece but with the sides open loosely attached by a few coloured bows ( which is holiday wear rather than proper swimwear).