Samsung Electronics GmbH
Hello,
no, it doesn't need it. You can use the LTE variant with an eSIM. Then independent use from other devices is possible. Or you can use the Galaxy Watch3 Bluetooth in conjunction with the paired smartphone.
Best regards from Schwalbach,
Your Samsung Service Team

No, of course not. First and foremost, the watch is connected to the mobile phone via Bluetooth. Only when the distance becomes too great does the watch switch to the WLAN (setting "WLAN automatic") to which the mobile phone is normally connected; then the watch is "remotely" connected to the mobile phone. If there is no known WLAN and/or no connection to the mobile phone, in other words if you are alone somewhere with the watch, the watch connects via the mobile network (4G), provided you have installed an e-SIM. As long as the watch is only connected via Bluetooth, the power consumption is at its lowest. When Wi-Fi is active, it increases, and when the mobile network is active, it is at its highest.