I prefer to wear a watch on the inside of my wrist - it feels unnatural to wear it on the outside. Is there a setting to change that?

There isn't a setting for that however, it should operate just fine while being worn that way.

If the screen is upside down, you'll need to change the orientation by going here:

On your phone, open the My Watch app.

Then click on General, then click Watch Orientation.

Apple's documentation used to state that it needed to be worn on the top of your wrist. However, the current support article doesn't seem to mention that at an all.

Wearing your Apple Watch - Apple Support

Lots of people in the forums have reported that it works fine on the inside of the wrist.

Oh boy! IdrisSeabright is right!

From within the link that he provided, it does say that it needs to be worn on the top of the wrist. But... like he also said, and I've seen it time and time again too, there are a several people who wear them under their wrists.

So, just beware that you may or may not get the most accurate readings possible.

Oh, that's where it is! I was looking in the wrong article.