Smartwatch operating systems compared
Short answer: The operating system decides which phone you can use, which apps you can add and how the watch is updated. Our catalog lists 83 different operating systems across 311 models. The largest groups are Proprietary (RTOS) (67 models), Garmin OS (31) and Mibro OS (23).
Last verified September 26, 2026.
What the operating system changes
It sets how you install apps, how notifications look, how health data is stored and which phone pairs fully. A watch with a maker's own system, such as a Garmin or Zepp watch, usually has fewer third-party apps but often a longer battery. A watch on a big platform has more apps but may need charging more often. Treat this as a tendency in the listings, not a rule.
Operating systems in the catalog
| Operating system | Models | Brands | Works with iPhone | Works with Android | Approx. rows |
|---|---|---|---|---|---|
| Proprietary (RTOS) | 67 | 17 | 67 | 67 | 0 |
| Garmin OS | 31 | 1 | 31 | 31 | 0 |
| Mibro OS | 23 | 1 | 23 | 23 | 0 |
| HarmonyOS | 21 | 1 | 21 | 21 | 0 |
| Zepp OS | 17 | 1 | 17 | 17 | 0 |
| KOSPET OS | 15 | 1 | 15 | 15 | 0 |
| COROS OS | 6 | 1 | 6 | 6 | 0 |
| Fitbit OS | 6 | 1 | 6 | 6 | 0 |
| HyperOS (RTOS) | 6 | 1 | 6 | 6 | 0 |
| Amazfit OS (RTOS) | 5 | 1 | 5 | 5 | 0 |
| Polar (RTOS) | 5 | 1 | 5 | 5 | 0 |
| SaveFamily OS (parent app) | 5 | 1 | 5 | 5 | 0 |
| Suunto OS | 5 | 1 | 5 | 5 | 0 |
| RTOS | 4 | 1 | 4 | 4 | 0 |
| ASUS HealthConnect (RTOS) | 3 | 1 | 3 | 3 | 0 |
| MagicOS (RTOS) | 3 | 1 | 3 | 3 | 0 |
| Wear OS | 3 | 2 | 0 | 3 | 0 |
| imoo OS (parent app) | 3 | 1 | 3 | 3 | 0 |
| MIUI Watch (RTOS) | 2 | 1 | 2 | 2 | 0 |
| Mibro OS (parent app) | 2 | 1 | 2 | 2 | 0 |
| Polar Flow | 2 | 1 | 2 | 2 | 0 |
| PolarOS | 2 | 1 | 2 | 2 | 0 |
| Proprietary (RTOS; Motorola license) | 2 | 1 | 2 | 2 | 0 |
| Wear OS + One UI Watch | 2 | 1 | 0 | 2 | 0 |
| Wear OS + One UI Watch 8 | 2 | 1 | 0 | 2 | 0 |
| Wear OS 3.5 | 2 | 1 | 0 | 2 | 0 |
| Wear OS 3.5 · One UI Watch (still updated) | 2 | 1 | 0 | 2 | 0 |
| Wear OS 4 + RTOS (dual-engine) | 2 | 1 | 0 | 2 | 0 |
| Wear OS 4 · One UI Watch 5 (still updated) | 2 | 1 | 0 | 2 | 0 |
| Wear OS 5 · One UI Watch 6 (still updated) | 2 | 1 | 0 | 2 | 0 |
| Withings OS | 2 | 1 | 2 | 2 | 0 |
| Xiaomi HyperOS 3 | 2 | 1 | 2 | 2 | 0 |
| Zepp OS 6 | 2 | 1 | 2 | 2 | 0 |
| watchOS 10 (still updated) | 2 | 1 | 2 | 0 | 0 |
| watchOS 26+ | 2 | 1 | 2 | 0 | 0 |
| watchOS 27 | 2 | 1 | 2 | 0 | 0 |
| Android 8.1 (parent app) | 1 | 1 | 1 | 1 | 0 |
| Anio RTOS (parent app) | 1 | 1 | 1 | 1 | 0 |
| BlueOS (RTOS) | 1 | 1 | 1 | 1 | 0 |
| Fitbit Ace app | 1 | 1 | 1 | 1 | 0 |
| FreeRTOS | 1 | 1 | 0 | 1 | 0 |
| Gabb (parent app) | 1 | 1 | 1 | 1 | 0 |
| Garmin (Connect app) | 1 | 1 | 1 | 1 | 0 |
| Garmin Jr. app | 1 | 1 | 1 | 1 | 0 |
| GizmoHub (parent app) | 1 | 1 | 1 | 1 | 0 |
| HarmonyOS 4 | 1 | 1 | 1 | 1 | 0 |
| HarmonyOS 5 | 1 | 1 | 1 | 1 | 0 |
| HyperOS 2 (RTOS) | 1 | 1 | 1 | 1 | 0 |
| KidiWatch (parent app) | 1 | 1 | 1 | 1 | 0 |
| MIUI (RTOS) | 1 | 1 | 1 | 1 | 0 |
| None (works via the Google Health app) | 1 | 1 | 1 | 1 | 0 |
| Nothing OS | 1 | 1 | 1 | 1 | 0 |
| OnePlus OS (BES2800BP) | 1 | 1 | 1 | 1 | 0 |
| Polar firmware | 1 | 1 | 1 | 1 | 0 |
| Proprietary (Withings) | 1 | 1 | 1 | 1 | 0 |
| SaveFamily OS | 1 | 1 | 1 | 1 | 0 |
| SaveFamily OS (family app) | 1 | 1 | 1 | 1 | 0 |
| SaveFamily OS (secure Play) | 1 | 1 | 1 | 1 | 0 |
| Spacetalk (parent app) | 1 | 1 | 1 | 1 | 0 |
| Suunto firmware | 1 | 1 | 1 | 1 | 0 |
| TickTalk OS | 1 | 1 | 1 | 1 | 0 |
| Tizen 5.5 (updates ended) | 1 | 1 | 0 | 1 | 0 |
| Watch-Me (family app) | 1 | 1 | 1 | 1 | 0 |
| Wear OS 3.5 (updates ended Oct 2025) | 1 | 1 | 0 | 1 | 0 |
| Wear OS 4 (updates to Oct 2026) | 1 | 1 | 0 | 1 | 0 |
| Wear OS 5 (updates to Oct 2027) | 1 | 1 | 0 | 1 | 0 |
| Wear OS 5 (upgradeable to 6) | 1 | 1 | 0 | 1 | 0 |
| Wear OS 6 | 1 | 1 | 0 | 1 | 0 |
| Wear OS 6 + OxygenOS Watch 8 | 1 | 1 | 0 | 1 | 0 |
| Wear OS 7 · One UI 9 Watch | 1 | 1 | 0 | 1 | 0 |
| Xiaomi HyperOS | 1 | 1 | 1 | 1 | 0 |
| Xiaomi HyperOS 2 | 1 | 1 | 1 | 1 | 0 |
| Xiaomi HyperOS~ | 1 | 1 | 1 | 1 | 1 |
| Xiaomi Kids app | 1 | 1 | 1 | 1 | 0 |
| Xplora OS | 1 | 1 | 1 | 1 | 0 |
| Zepp OS 2 | 1 | 1 | 1 | 1 | 0 |
| Zepp OS 3 | 1 | 1 | 1 | 1 | 0 |
| imoo OS | 1 | 1 | 1 | 1 | 0 |
| myFirst Circle (parent app) | 1 | 1 | 1 | 1 | 0 |
| one2track (parent app) | 1 | 1 | 1 | 1 | 0 |
| watchOS 11 (still updated) | 1 | 1 | 1 | 0 | 0 |
| watchOS 26 | 1 | 1 | 1 | 0 | 0 |
| watchOS 9 (still updated) | 1 | 1 | 1 | 0 | 0 |
Which phone works with which system
Some systems pair with only one platform and some pair with both. See smartwatch phone compatibility for the full table by brand, and Apple Watch with Android for the most asked case.
Systems that run on one brand only
| Operating system | Brand | Models |
|---|---|---|
| Garmin OS | Garmin | 31 |
| Mibro OS | Mibro | 23 |
| HarmonyOS | Huawei | 21 |
| Zepp OS | Amazfit | 17 |
| KOSPET OS | Kospet | 15 |
| COROS OS | COROS | 6 |
| Fitbit OS | Fitbit | 6 |
| HyperOS (RTOS) | Xiaomi | 6 |
| Amazfit OS (RTOS) | Amazfit | 5 |
| Polar (RTOS) | Polar | 5 |
| SaveFamily OS (parent app) | SaveFamily | 5 |
| Suunto OS | Suunto | 5 |
| RTOS | HONOR | 4 |
| ASUS HealthConnect (RTOS) | ASUS | 3 |
| MagicOS (RTOS) | HONOR | 3 |
| imoo OS (parent app) | Imoo | 3 |
| MIUI Watch (RTOS) | Xiaomi | 2 |
| Mibro OS (parent app) | Mibro | 2 |
| Polar Flow | Polar | 2 |
| PolarOS | Polar | 2 |
| Proprietary (RTOS; Motorola license) | Motorola | 2 |
| Wear OS + One UI Watch | Samsung | 2 |
| Wear OS + One UI Watch 8 | Samsung | 2 |
| Wear OS 3.5 | Xiaomi | 2 |
| Wear OS 3.5 · One UI Watch (still updated) | Samsung | 2 |
| Wear OS 4 + RTOS (dual-engine) | OnePlus | 2 |
| Wear OS 4 · One UI Watch 5 (still updated) | Samsung | 2 |
| Wear OS 5 · One UI Watch 6 (still updated) | Samsung | 2 |
| Withings OS | Withings | 2 |
| Xiaomi HyperOS 3 | Xiaomi | 2 |
| Zepp OS 6 | Amazfit | 2 |
| watchOS 10 (still updated) | Apple | 2 |
| watchOS 26+ | Apple | 2 |
| watchOS 27 | Apple | 2 |
| Android 8.1 (parent app) | Kidiwatch | 1 |
| Anio RTOS (parent app) | Anio | 1 |
| BlueOS (RTOS) | Vivo | 1 |
| Fitbit Ace app | Fitbit | 1 |
| FreeRTOS | Samsung | 1 |
| Gabb (parent app) | Gabb | 1 |
| Garmin (Connect app) | Garmin | 1 |
| Garmin Jr. app | Garmin | 1 |
| GizmoHub (parent app) | Verizon | 1 |
| HarmonyOS 4 | Huawei | 1 |
| HarmonyOS 5 | Huawei | 1 |
| HyperOS 2 (RTOS) | Xiaomi | 1 |
| KidiWatch (parent app) | Kidiwatch | 1 |
| MIUI (RTOS) | Xiaomi | 1 |
| None (works via the Google Health app) | Fitbit | 1 |
| Nothing OS | Nothing | 1 |
| OnePlus OS (BES2800BP) | OnePlus | 1 |
| Polar firmware | Polar | 1 |
| Proprietary (Withings) | Withings | 1 |
| SaveFamily OS | SaveFamily | 1 |
| SaveFamily OS (family app) | SaveFamily | 1 |
| SaveFamily OS (secure Play) | SaveFamily | 1 |
| Spacetalk (parent app) | Spacetalk | 1 |
| Suunto firmware | Suunto | 1 |
| TickTalk OS | TickTalk | 1 |
| Tizen 5.5 (updates ended) | Samsung | 1 |
| Watch-Me (family app) | WatchMe | 1 |
| Wear OS 3.5 (updates ended Oct 2025) | 1 | |
| Wear OS 4 (updates to Oct 2026) | 1 | |
| Wear OS 5 (updates to Oct 2027) | 1 | |
| Wear OS 5 (upgradeable to 6) | OnePlus | 1 |
| Wear OS 6 | OPPO | 1 |
| Wear OS 6 + OxygenOS Watch 8 | OnePlus | 1 |
| Wear OS 7 · One UI 9 Watch | Samsung | 1 |
| Xiaomi HyperOS | Xiaomi | 1 |
| Xiaomi HyperOS 2 | Xiaomi | 1 |
| Xiaomi HyperOS~ | Xiaomi | 1 |
| Xiaomi Kids app | Xiaomi | 1 |
| Xplora OS | Xplora | 1 |
| Zepp OS 2 | Amazfit | 1 |
| Zepp OS 3 | Amazfit | 1 |
| imoo OS | Imoo | 1 |
| myFirst Circle (parent app) | myFirst | 1 |
| one2track (parent app) | One2Track | 1 |
| watchOS 11 (still updated) | Apple | 1 |
| watchOS 26 | Apple | 1 |
| watchOS 9 (still updated) | Apple | 1 |
How to choose
Start from your phone, then pick the features you use daily, then check the system. If you want to install many third-party apps, choose a system with an app store. If you want battery life and simple health tracking, a maker's own system is often enough. If you may change phones soon, check cross-platform support first.
Before you buy
Check how long the maker updates the watch, whether the app store is available in your country and whether setup needs the maker's app. Features change with updates. Check the maker's current details. See also smartwatch battery life explained and our methodology.