As usual men's and women's dress code in public establishments such as swimming pools may be partly stricter than, for instance, on city public beaches, also women's dress code demanded in indoor swimming pools is somewhat stricter than outdoor swimming pools. For instance, there are some countries where women and girls can become sunburned while lying topless on the beach, but this behavior is usually not permitted in a pool, especially in indoor swimming pools.
A reversal of these rules is also general, e.g. men's and women's dress code in swimming pools is somewhat stricter than beaches. Wearing shirt and shoes is acceptable on a beach, but usually not in a swimming pool, but as a rule indoor pools women's and men's undress codes are stricter than outdoor pools: men usually wear T-shirts for protection from sunburn or for modesty in outdoor swimming pools, and as you probably know men are not ordinarily permitted to wear T-shirts in such public places as indoor swimming pools.
There is nothing uncommon when someone is swimming with clothes on (for instance, as practical exercises for the drowning averting, because someone might fall out from a boat clothed), but such a situation usually causes objections from pools lifeguards, especially at indoor swimming pools.
Many people like to swim with their clothes on and usually like to wear beachwear at beaches, in spite of this, at public swimming pools (there is no difference whether it is indoor or outdoor pool) more minimal men's and women's dress code, such as one-piece bathing suits of Lycra for women and briefs of Lycra for men are often worn. For towers diving probably 10m high, at times it is allowed to double up bathing suits (i.e., men usually wear one brief outside another one) and that's why the possibility of swimsuit ripping after impact with the surface of water reduces.
But even the strictest dress code rules have some concessions and that's why some public swimming indoor and outdoor pools have some special hours for nude swimming, and moreover nudity is even required by some swimming pools. Not long ago, many pools which belong to YMCA required visitors to have some special bathing suits, which are made of special materials that will not result in soiling of the pool or to be naked; "nylon bathing suit or no bathing suit" - this is the main slogan which was used in those swimming pools.
More recently, men's and women's dress code in most swimming pools has been mitigated to permit for additional moderation. There was one main rule, if you can prove to pool operators that you have the second set of clothes and those clothes are only for pool use and you are compliant to go to the showers in your second set of clothes in this case pool operators can allow you to swim clothed.
Thus, now you know that there are some places where special dress code is required. So, if you have decided to visit swimming pool, you should choose comfortable and stylish indoor and outdoor pools dress code, because there are strict rules concerning clothes at pools in contrast to beach dress code, which you can wear in at a beach. Indoor and outdoor pools and beach dress code is available in every dress code shop.
I still think if their body compliments it, than women should wear as little as possible. This may not happen in my lifetime, but one can always hope.