Samsung's compatibility list shows which Gear S3 features work with the iPhone and non-Samsung devices - SamMobile - SamMobile
Gear S3 compatibility list for Android and iOS – Samsung Rumors
Buy Compatible for Samsung Gear S3 FrontierClassic Case Bezel Cover, Metal Bezel TPU Protector Bumper Case, Also Fit for 2018 Released Galaxy Watch 46mmNOT for 2021 Galaxy Watch 4 Classic 46mm Online
Samsung's Gear S3, Gear S2, & Gear Fit2 wearables are now compatible with iOS - 9to5Mac
Amazon.com: Compatible with Samsung Galaxy Watch 3 45mm Band - Gear S3 Frontier & Classic Bands/Galaxy Watch 46mm bands, 22mm Soft Silicone Replacement Black Bands Sports Straps Breathable Men and Women :