bp1000:
I've installed the latest iOS and watchOS releases and the watch app shows Spark now support a cellular plan. I'm overseas for a couple of days so I can't finish the setup until I'm back.
It is annoying as a customer that these plans don't work when you are roaming - that is, the watch doesn't have cellular connection.
This isn't a limitation of Spark. All carriers internationally seem to have a note that the Apple Watch cannot roam