Hi
Apple Watch Series 3 (GPS + Cellular) is not locked to any specific carrier and has a built-in eSIM that copies information from the iPhone's SIM card.
The built-in cellular feature cannot be used when roaming.
The built-in cellular feature requires a carrier plan for your iPhone in your country of use that specifically includes support for Apple Watch Series 3 (GPS + Cellular), including the carrier activating the device on the plan.
If buying Apple Watch Series 3 (GPS + Cellular) in another country, then, in order to use the built-in cellular feature, you would need to buy a model that supports the relevant LTE and UMTS bands for your intended country of use and your supported carrier there.
There are three different regional versions of Apple Watch Series 3 (GPS + Cellular), each supporting different LTE and UMTS bands, as detailed here - as you have identified, Apple lists the same models for Germany and Hong Kong:
Apple Watch - Carriers - Apple
If in doubt, I suggest that you contact your intended carrier to ask whether any given model can be used on their network with a plan that they may offer or plan on offering for iPhone that supports Apple Watch Series 3 (GPS + Cellular).
Apple Watch Series 3 (GPS + Cellular) can be used without activating the built-in cellular feature, in which case it functions like a GPS-only model, in conjunction with an iPhone 6 or newer model of iPhone (running the latest version of iOS) and a service plan from any carrier.
The warranty terms for an Apple Watch purchased in Hong Kong and Germany, respectively, are are detailed here:
Hi
Apple Watch Series 3 (GPS + Cellular) is not locked to any specific carrier and has a built-in eSIM that copies information from the iPhone's SIM card.
The built-in cellular feature cannot be used when roaming.
The built-in cellular feature requires a carrier plan for your iPhone in your country of use that specifically includes support for Apple Watch Series 3 (GPS + Cellular), including the carrier activating the device on the plan.
If buying Apple Watch Series 3 (GPS + Cellular) in another country, then, in order to use the built-in cellular feature, you would need to buy a model that supports the relevant LTE and UMTS bands for your intended country of use and your supported carrier there.
There are three different regional versions of Apple Watch Series 3 (GPS + Cellular), each supporting different LTE and UMTS bands, as detailed here - as you have identified, Apple lists the same models for Germany and Hong Kong:
Apple Watch - Carriers - Apple
If in doubt, I suggest that you contact your intended carrier to ask whether any given model can be used on their network with a plan that they may offer or plan on offering for iPhone that supports Apple Watch Series 3 (GPS + Cellular).
Apple Watch Series 3 (GPS + Cellular) can be used without activating the built-in cellular feature, in which case it functions like a GPS-only model, in conjunction with an iPhone 6 or newer model of iPhone (running the latest version of iOS) and a service plan from any carrier.
The warranty terms for an Apple Watch purchased in Hong Kong and Germany, respectively, are are detailed here:
Hi Julian, as far as I know it will work.
Apple iWatch Cellular usage in HongKong and Germany
