Apple Watch series 3

FYI, it is a silver (as opposed to space gray) aluminum and yes, if you get the silver, it looks like it only comes with a white sports band:

Buy Apple Watch Series 3 - Apple

https://www.apple.com/watch/compare/

https://support.apple.com/kb/SP766?viewlocale=en_US&locale=en_US

I'm sorry, I've not looked at that in a while. I'm not aware why they only allow you to choose the white sport band. I know that you can order different bands when you purchase the Series 6. You can, however, purchase other bands if you wish, so long as the size you order is for the same size Watch, i.e. 38mm or 42mm. My guess is that it is because it is the older version Watch.

You should be able to select any color watch band. Are you attempting to make this order online with Apple?