A GPS Smartwatch is a watch that records a run, a ride or a trail directly from satellites without relying on your phone. Older models used single-frequency GPS, but the defining trait of this category today is multi-band, also called dual-frequency, GNSS. The watch listens to the L1 and L5 frequencies at once and adds the GLONASS, Galileo, QZSS and BeiDou constellations alongside GPS. That combination produces a noticeably cleaner track than a single-band receiver in places that wreck a signal, like the street canyons between tall buildings or under dense tree cover. The reliability of your distance and pace data is what separates this category from an ordinary smartwatch.
On the Garmin side, the Forerunner 970 uses SatIQ to switch satellite mode automatically based on terrain and has an RRP around £630, while the Forerunner 965 offers dual-band GPS near £480. The Fenix 8 43mm AMOLED runs Garmin's Multi-Band GNSS mode from roughly £949. Apple Watch Ultra 3 starts around £749 with L1 and L5 dual-frequency GPS plus a second-generation Ultra Wideband chip for Precision Finding. Coros covers the spread: the titanium Apex 4 with full offline maps lands near £429, the Vertix 2S at £599, and the entry Pace 4 around £229. Polar's Grit X2 Pro is £649, and Suunto's Vertical 2 sits near £529.
When you buy, look first at what constant multi-band does to battery life, because the most accurate mode draws more power, which is exactly why Garmin's SatIQ auto-switching matters on long efforts. If you run in a city, L5 support genuinely cuts the canyon and tree-cover errors; if you mostly run a flat track, single-band is usually fine. Offline maps, a barometric altimeter and a true touch AMOLED screen are what pay off for mountain and trail users. On budget models, always confirm whether multi-band runs continuously or only in a special mode you have to select.
The category splits into two camps. On one side are the sport-first watches from Coros and Suunto that run for weeks; on the other are the notification, app and ecosystem-strong AMOLED watches from Apple and Garmin. Triathletes usually lean toward Garmin or Coros for multi-sport profiles and long battery, while for a daily wearer the positioning accuracy on the Apple Watch Ultra 3 is already more than enough. The right pick comes down to where you run and how you weigh accuracy against battery.