Yes, you absolutely can shower with press on nails. It is a common misconception that press on nails will be washed away by water, in the same way that make-up would, but this simply isn’t the case. In fact, press on nails are usually quite hardy once they have stuck down.
But, while you can shower with press on nails, it is very important that you do not rush to do this. Most press on nails stick down with glue, and this glue will take time to set. So, you definitely can shower with press on nails on your fingers, but you shouldn’t do so until at least 2 hours after sticking your nails down. In an ideal situation, you should give the glue as long as possible to set before you go in the shower.
This is one of the main reasons why a lot of people choose to stick their press on nails down either before bed, or after they have taken a shower. If you stick your nails down immediately before bed, then the glue will have a solid 8+ hours to set before you use your fingers next. Alternatively, if you do it immediately after showering, you know that you will not be getting the glue wet for the foreseeable future.
So, yes, you can shower with press on nails, so there is no need to avoid doing this. The only time that you should avoid getting your press on nails wet is within the first 2 hours after sticking them down.