turn off passcode on apple watch

I have ios 11 Apple watch Series 1 and iphone 7+. I'm already logged into my phone and watch. I have a 2 part question. On my watch, if I go to settings and turn off passcode, do I need to enter my current passcode to do it, or will just turn it off? Same with using the apple watch app on the phone. Do I need to enter my passcode to turn it off, or does it just turn off? Just curious. My nephew loves to look at pictures on my phone, and he's older now and may wander.