Garmin only recently introduced dual-frequency GNSS in some versions of their Fenix 7 watches, and have since added it to some cheaper models like the Forerunner 255. The first watch with L1+L5 was the Coros Vertix 2 from last year, so it's still quite new in watches.

Qualcomm has had it since the Snapdragon 855 though, so basically every flagship Android phone since 2019.

https://support.garmin.com/en-IE/marine/faq/9NWiPDU4gM0JWMfd...