Hopefully you like one the Apple Watch's built-in watch faces, because Apple isn't about to let you replace them. In an update to its App Store guidelines today, spotted by 9to5Mac, Apple says that it will reject all Watch apps with the primary purpose of telling the time. Apple doesn't currently provide a way to install third-party watch faces, though using an app that just told the time could have served as a workaround. It wouldn't, by any means, be a good work around — it could lead to battery life issues and general performance problems — so it's not entirely surprising that Apple is prohibiting them.
Will Apple ever allow custom faces?
This doesn't mean that Apple will never allow custom faces on the Watch, but some people are guessing that'll turn out to be the case. Apple pundit John Gruber discussed the possibility on his blog Daring Fireball earlier this month, concluding that Apple probably wouldn't open watch faces up in the same way that it hasn't opened up the lock and home screens on the iPhone and iPad. In part, he points to an ugly collection of user-made Android Wear watch faces for reason why Apple may not want to allow this. His suspicion is that if Apple does let others step in, it'll be through specific partnerships — not an open store.
Either way, Apple has other areas of the Watch to open up to developers first. Specifically, that includes the ability to make native apps, which are supposed to arrive later this year. Apple is constantly refining its App Store guidelines, but it's hard to imagine that native apps would change this one, simply given the behavior of the Watch. If you're not happy with the watch face options that Apple provides, you aren't entirely out of luck, however. 9to5Mac also points out that Apple, in its Watch help section, tells owners to keep their eyes peeled for new faces after each software update. "Check frequently for software updates," it says. "The set of watch faces that follows might differ from what you see on your Apple Watch."