When the feature is enabled in Settings, your phone will detect the type of cellular plan being used, and whether or not you're roaming. (android.gadgethacks.com)
Just watch your data downloads if you're on a limited cellular plan! (techradar.com)
T - Mobile's basic cellular plan for the Apple Watch Series 3 tied to the T - Mobile ONE plan called for unlimited data on LTE, but only at 512kbps for $ 10 per month after AutoPay enrollment. (pocketnow.com)