Question about Apple Watch Series 10

You cannot insert a physical SIM card in the Apple Watch Series 10 (46 mm, Wi-Fi only) as it does not have a SIM card slot. Instead, the Apple Watch uses eSIM technology, which enables a mobile connection via a mobile phone provider, but only on models with a cellular function. The model described here only supports Wi-Fi, so you cannot use it directly with a SIM card like a smartphone.