on 23-12-2020 10:07
You need a watch 3 or active 2 as they are the only ones supported for esim.
You then need an esim and watch data plan to use your watch as a standalone item.
Any other watch will only connect via Bluetooth so a data plan is not required for those.
OnePlus 6 (O2 & Sfr), Z3 Tablet (Three UK), iPhone 8+ (EE)