What to do if the region where the Apple Watch ECG is located does not work

None of the non-Chinese phone pairs with the Hong Kong version of the watch can successfully activate the ECG function. A small line below the ECG setup screen says: During setup, your location will be used to confirm that the sub-function is available in your region. So whenever you're in a region or country other than the one that supports ECG, you'll be prompted with the message: The ECG app is not available in your region. Apple is supposedly utilizing carrier base stations for location. In other words, if you want to use the ECG feature on your Hong Kong version of Apple Watch 4, you have to use a Hong Kong SIM card and then go to Hong Kong to use it, and you can't do either operation without it. Of course, if Apple's ECG feature gets approved in mainland China in the future, then you can use it without any hassle. But there's no telling how long this wait will be, it could be a year and a half, or it could be unavailable forever.