Apple Watch Series 9 vs Garmin Forerunner 255
The Verdict
Apple Watch Series 9 excels with its vibrant Always-On Retina LTPO OLED display (484 x 396 resolution) and comprehensive health sensors including ECG and skin temperature monitoring. WatchOS 10 offers seamless iPhone integration with extensive app support. However, battery life maxes out at 18 hours, requiring daily charging. Garmin Forerunner 255 targets serious athletes with exceptional battery longevity: 14 days in smartwatch mode and 30 hours with GPS active. Its MIP transflective display suits outdoor workouts better than OLED in bright sunlight. While lacking ECG and skin temperature tracking, it delivers robust running metrics and superior endurance for fitness-focused users. Apple wins for overall features and display quality, but Garmin's $50 lower price and multi-week battery life make it ideal for runners and outdoor enthusiasts who prioritize practicality over smartwatch versatility.
Who Should Buy
Buy the Apple Watch Series 9 if…
- →S9 chip enables on-device Siri and the new Double Tap gesture
- →Comprehensive health suite: ECG, SpO2, temperature, crash detection
- →Brightest Apple Watch display at up to 2000 nits
Buy the Garmin Forerunner 255 if…
- →14-day battery life means weekly charging at most
- →Multi-band GPS for exceptional outdoor tracking accuracy
- →Morning Report with daily training readiness and HRV status
Category Scores
Pros & Cons
Apple Watch Series 9
Pros
- S9 chip enables on-device Siri and the new Double Tap gesture
- Comprehensive health suite: ECG, SpO2, temperature, crash detection
- Brightest Apple Watch display at up to 2000 nits
- Seamless deep integration with iPhone and Apple ecosystem
- Wide variety of bands and cases for personalization
Cons
- 18-hour battery life requires daily charging
- Only useful if you own an iPhone — no Android support
- Cellular model adds significant ongoing carrier cost
- Incremental upgrade over Series 8 for existing owners
Garmin Forerunner 255
Pros
- 14-day battery life means weekly charging at most
- Multi-band GPS for exceptional outdoor tracking accuracy
- Morning Report with daily training readiness and HRV status
- Race Predictor estimates finish times for 5K to marathon
- Lightweight at 49 g and comfortable for 24/7 wear
Cons
- MIP display lacks the vibrancy of AMOLED competitors
- No touchscreen on base model — button-only navigation
- No ECG or blood pressure monitoring
- Limited smart features compared to Apple Watch or Wear OS
- Third-party app ecosystem is small
Full Specifications
| Spec | Apple Watch Series 9 | Garmin Forerunner 255 |
|---|---|---|
| Software | watchOS 10 | Garmin proprietary OS |
| Body | ||
| Weight | 38.7 g (aluminum) | 49 g |
| Case material | Aluminum or stainless steel | Fiber-reinforced polymer |
| Water resistance | WR50 / EN13319 | 5ATM |
| Health & Sensors | ||
| ECG | ||
| SpO₂ | ||
| Skin temperature | ||
| Heart rate | ||
| Sleep tracking | ||
| Battery | ||
| Battery life | Up to 18 hrs, up to 36 hrs Low Power Mode | Up to 14 days (smartwatch), 30 hrs GPS |
| Display | ||
| Size | 45 mm | 46mm |
| Type | Always-On Retina LTPO OLED | MIP (Memory-in-Pixel) transflective |
| Always-on display | ||
| Resolution | 484 x 396 | 260 x 260 |
| Processor | ||
| RAM | 1 GB | — |
| Chipset | Apple S9 SiP | Garmin custom SoC |
| Connectivity | ||
| GPS | ||
| NFC | ||
| Wi-Fi | ||
| Cellular | ||
| Bluetooth | 5.3 | 5.0 |
Related Comparisons
This comparison is based on verified manufacturer specifications covering display, performance, camera, battery, and build quality. Scores are generated by analyzing specs across weighted categories on a 10-point scale. Learn more about our methodology.
Explore more in smartwatches, see all Apple products or all Garmin products. View full details for the Apple Watch Series 9 or the Garmin Forerunner 255.