GPS Eco-Drive is the combination that defines Citizen's Satellite Wave line: a light-charged Eco-Drive cell paired with a receiver that pulls time and time-zone data straight from GPS satellites. The journey began with the F100 in 2014, which locked onto a satellite signal in roughly three seconds and gives correct local time across 40 time zones based on where you are standing. Unlike radio-controlled watches, you need not be near a transmitter; as long as you have open sky, you can trigger a manual sync anywhere on the planet. And because it is Eco-Drive, there is no battery to replace, ever.
Look at the real watches and the multifunction flagships are the F900 and its successor the F990. The F900 arrived at Baselworld 2015 at roughly £1,900, carrying a 1/20-second chronograph, perpetual calendar, alarm, dual time and a light-level indicator in a case around 13mm thick. The 2018 F990 added a twin-coil motor that doubled hand speed, in a larger case near 48.5mm, including Promaster Sky and anniversary editions capped at 1,500 pieces. If you want something slimmer and dressier, the F150 (Satellite Wave World Time GPS, sold as Freedom) sits around 12.5mm with a more classic layout. The current high end is the F950 under the Attesa banner: 2024-2025 references such as the CC4059-64L, CC4074-61W and CC4104-53E run Super Titanium cases near 44.6mm, 100m of water resistance and a perpetual calendar good to 2100, priced roughly £1,600 to £1,750.
Buying one starts with how you actually live. If you fly often and cross time zones, GPS Eco-Drive is a genuine convenience: land, press a button, and the watch jumps to local time without a phone. The obvious rival here is the Seiko Astron GPS Solar; the Astron attempts a daily auto-adjust while Citizen typically syncs on an interval (around every 72 hours) plus manual reception, and both need daylight saving set by hand because GPS does not broadcast it. If you want Super Titanium, the Attesa F950 is light and at least five times harder than steel, with some references finished in black Duratect DLC. For a more traditional look at a lower price, the steel or ion-plated F150 makes more sense.
One honest caveat: these are analogue GPS watches, not smartwatches, so do not expect notifications or apps. What you get instead is movement-grade longevity and accuracy delivered from orbit. Cases mostly run 44mm and up, and the F900 and F990 can wear large on slimmer wrists, so try before you buy if you can. If you want a long-lived travel watch that never needs a battery and corrects itself anywhere on earth, GPS Eco-Drive fills exactly that gap.