International Roaming problem for Apple Watch eSIM

Not all international roaming partners are setup to deal with smartwatches.  If the local provider does not natively support standalone smartwarches on their network.  Those smartwatches are not going to work in standalone when roaming on to their network.

Watches make it really easy to leave your phone in your hotel room and stay connected while on adventures. While traveling outside the country, standalone watch plans don't support international roaming, so you would need to keep your phone with you to stay connected. The watch should be connected to your phone through the watch app or bluetooth, but it wont work all by itself. 

SoCal wrote:

I have an Apple Watch Ultra 2 with T-Mobile eSIM on the international roaming service. My phone works fine on international roaming while travel to Singapore and China. While the watch never response, keeping showing loading with T-Mobile. Does anyone know the answer? Gracias

I also faced this same issue with my SIM when I moved to Sweden. I searched many websites to solve this problem and found one that might help. Check this out to see if it's useful for you: https://tmsimregistration.info/