You should not open your eyes when you swim so as to see things which will make your eyes get infection. You should wear the swimming goggles to protect your eyes. In addition, you could also see things clearly. As we know, there is a lot of bacterium in the swimming pool which you need to avoid. You could go to the online store to buy the swimming glasses which will be so necessary for your swimming.
Yes, you can, but you had better not.
There are many dirty things in the water. Even if the water is clean, there must be chemical substance in it as it will be sterilized. When you are swimming with eyes open, the germs, dusk and chemical substance may enter your eyes. Your eyes may be infected and develop inflammation. You can wear a pair of swimming goggles to protect your eyes. If you really want to see things under water with bare eyes, when you finish swimming, don't forget to drip some eye drops in your eyes.
Ok, It sounds like you like to swim quite a lot. As a matter of fact, it would not be wise for you to swim with your eyes wide open, for the quality of pool water is usually bad, which contains a lot of harmful stuff, making your eyes irritated, even get infections. A pair of swimming goggles would get you free from those problems, and earns you great vision under water.