Garmin Fenix 8 Solar - 51mm Review

Our Analysis and Test Results

The Garmin Fenix 8 Solar - 51mm is a powerhouse designed for endurance athletes, outdoor adventurers, and those who demand top-tier GPS performance and durability. It builds upon its predecessors with improved solar charging, enhanced GPS accuracy, and longer battery life, all while maintaining the rugged and premium build quality that defines the Fenix lineup.

Here at the Outdoor GPS Shop we have sold and used this watch from the day it was launched in August 2024.

Garmin continues to differentiate the MIP (Memory-In-Pixel) display variant from its AMOLED counterparts, ensuring maximum efficiency in sunlight and extending battery life to impressive levels.

If your priority is reliability in extreme environments, superior battery life, and topographical mapping capabilities, the Fenix 8 Solar is an excellent investment.

Performance Comparison

GPS & Sensor Accuracy

The dual-frequency GNSS (Multi-Band GPS) provides exceptional accuracy in all terrains, from dense forests to deep canyons.

In real life testing against a precisely measured 2.8-mile reference route, the Fenix 8 Solar recorded 2.74 miles, showing minimal deviation of just 0.06 miles. This is one of the most accurate performances we’ve seen in a GPS watch.

For heart rate accuracy, we compared it against the Polar chest strap, a gold standard in heart rate measurement. The Fenix 8 Solar maintained a ±1.46 BPM deviation, demonstrating high precision even during high-intensity workouts.

Additionally, the watch includes an ECG sensor, Pulse Ox (SpO2) monitoring, respiration tracking, and advanced HRV analysis, making it a top-tier choice for endurance athletes looking to optimize performance and recovery.

Activity Tracking & Multi-Sport Performance

The Fenix 8 Solar - 51mm is built for serious athletes with its extensive sports modes, tracking everything from running and cycling to mountaineering, skiing, and ultra-endurance events.

• Running & Trail Running: The Fenix 8 Solar features advanced running dynamics, including ground contact time, vertical oscillation, stride length, and real-time stamina tracking. For trail runners, turn-by-turn navigation and ClimbPro ascent tracking provide key insights into elevation gains and pacing.
  
  
• Cycling & Mountain Biking: The watch integrates seamlessly with Garmin Edge GPS units, supports cycling power meters, and includes MTB-specific dynamics such as jump detection, flow rating, and grit score.
  
  
• Hiking & Mountaineering: With preloaded TOPO maps, next-gen breadcrumb navigation, and detailed route planning, the Fenix 8 Solar is perfect for backcountry adventurers.
  
  
• Swimming & Triathlon: The 5ATM water resistance, stroke tracking, and open-water GPS mode make it an excellent choice for swimmers and triathletes.
  
  
• Skiing & Snowboarding: The watch includes preloaded ski maps and avalanche risk alerts.

With over 100 activity profiles, there is no doubt that the Fenix 8 Solar is one of the most versatile multi-sport watches on the market.

Smartwatch Features & Everyday Use

Beyond sports, the Fenix 8 Solar functions as a full-featured smartwatch.

• Garmin Pay for contactless payments
• Music storage & streaming (Spotify, Amazon Music, Deezer)
• Smart notifications (read and reply to texts, take calls when connected to a phone)
• Garmin Connect IQ App Store for additional apps & widgets

Garmin’s redesigned UI makes it easier to navigate key insights on sleep tracking, stress monitoring, body battery energy tracking, and recovery time analysis.

Solar Charging & Battery Life

One of the biggest advantages of the Fenix 8 Solar is its outstanding battery performance:

• Standard GPS Mode: Up to 66 hours (expandable to 92 hours with solar charging)
• Expedition Mode: More than 2 months with solar input
• Smartwatch Mode: Up to 30 days per charge

In real-world conditions, we found that with moderate GPS use, solar charging easily extends battery life by 20-30%, making it an ideal watch for ultra-runners and long-distance adventurers.

Rugged Design & Build Quality

The 51mm case size provides a larger display and enhanced durability, featuring:

• Sapphire lens (scratch-resistant and ultra-durable)
• Titanium case (lightweight yet rugged)
• QuickFit bands (easily interchangeable, compatible with older Fenix models)
• 5ATM water resistance (suitable for swimming, heavy rain, and extreme conditions)

The watch’s built-in LED flashlight is a game-changer for night navigation and emergency situations, making it a unique feature that Garmin continues to perfect.

Navigation & Mapping

Garmin’s top-tier mapping features are one of the standout reasons to invest in the Fenix 8 Solar:

• Preloaded TopoActive Maps (Europe, US, and global regions available for download)
• Turn-by-Turn Navigation (like a GPS device, but on your wrist)
• ClimbPro Ascent Planner (perfect for mountaineering and hiking)
• Real-Time Breadcrumb Trail (ensuring you never get lost)

The multi-band GPS ensures precision in remote locations, making it a top choice for expedition-level adventures.

Should You Buy the Garmin Fenix 8 Solar?

If you’re looking for the most durable, feature-packed, and longest-lasting GPS watch on the market, the Garmin Fenix 8 Solar - 51mm is a phenomenal choice.

Who Should Buy It?

✅ Ultra-Runners & Endurance Athletes – Outstanding battery life, multi-band GPS, and real-time stamina tracking.
✅ Hikers, Backpackers & Mountaineers – Topo maps, ClimbPro, weather forecasting, and turn-by-turn navigation.
✅ Cyclists & Triathletes – Power meter compatibility, VO2 max tracking, and interval training support.
✅ Adventurers & Expedition Travelers – Unmatched durability, emergency features, and solar charging capabilities.

Who Might Want to Look Elsewhere?

❌ Casual Athletes – If you don’t need all the advanced features, a Forerunner 965 or Instinct 2X Solar may be a better fit.
❌ Budget-Conscious Users – The Suunto Vertical Titanium Solar offers similar battery performance at a lower cost.
❌ Those Who Prefer AMOLED Displays – Consider the Garmin Fenix 8 - 51mm Amoled Sapphire if screen brightness and vibrancy are a priority.

Final Verdict

The Garmin Fenix 8 Solar - 51mm is arguably the best adventure GPS watch available today. With exceptional GPS accuracy, best-in-class solar battery life, detailed mapping, and rugged durability, it is an outstanding investment for serious athletes and outdoor enthusiasts.

If you want the most reliable GPS watch money can buy, this is it. Highly recommended.