Personally, you are not allow to wear contact lenses when you swim. It is really dangerous and risk to wear contact lenses when you swim. It sounds practical to wear contact lenses inside and swim goggles outside. However, you shall make sure that no water can leak into your goggles and you never take off/on your swim goggle since from you jump into water. Anyway, this is not a good method for vision aids when you swim. Perhaps, you can search a pair of prescription swimming goggle online. It could be helpful for you. Good luck.
There are many invisible bacterial in no matter lake water or swimming pool. So, it is risk of eye infection by wearing contact lenses for a swimming. And it can cause many eye problems if you swim with contact lenses. If you just want to get vision aids and eye protection, you can buy prescription swimming goggles. I saw many online eyeglasses shop provide it at affordable price. You You can have a try. Good luck.
If you need vision correction while swimming in lakes and rivers, try a pair of prescription swimming goggles. Pools do not harbor as many microorganisms as lakes and rivers, so the risk of infection is lower. If worn in the pool, contact lenses may absorb chlorine and cause eye irritation.