A bund strap has always been a great option for a bold, but classic look for your timepiece and now Head Porter has got one designed specifically for the Apple Watch. The leather has a faux-croc pattern for an exotic look and you can remove it if you just want to wear the strap on its own. It's also cut a hole cut out in the back so you can still have full use of the sensors. 

The strap is designed for both the 38/40mm and 42/44mm Apple Watches. 

$246, store.headporter.co.jp