The battle of rugged smartwatches is heating up, and today we’re answering the big question—is the Garmin Fenix 8 really better than the Amazfit T-Rex 3? And more importantly, which one is the right fit for you?
Both the Garmin Fenix 8 and the Amazfit T-Rex 3 bring durability, GPS accuracy, and outdoor tracking features, but they differ in price, performance, and functionality. To make this comparison as fair as possible, I’m using the 47mm AMOLED version of the Fenix 8, which is closest in size and hardware specs to the T-Rex 3.
In this deep dive, we’ll be covering more than 10 crucial categories, including design, battery life, GPS accuracy, sports tracking, health features, and smart capabilities.
By the end of this detailed breakdown, you’ll know exactly which rugged smartwatch suits your lifestyle, budget, and needs.
So, if you’ve been debating between these two watches, you’re in the right place—let’s get started!
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Accessories
Starting from the accessories, Garmin offers a much wider variety compared to Amazfit. While most accessories aren’t essential, they are crafted with premium materials, ensuring durability and long-term reliability.
One notable area where Garmin excels is in its straps. The official Garmin straps are well-made, secure, and comfortable, making them a smart investment. In contrast, cheaper third-party straps often lack the same level of reliability, and losing your expensive smartwatch due to a weak strap is the last thing you want.
So, while Amazfit offers basic accessories, Garmin’s ecosystem is more refined, giving users higher-quality add-ons that enhance the overall experience. If accessory variety and quality matter to you, Garmin takes the win in this category.
Design & Build Quality
Both the Garmin Fenix 8 and the Amazfit T-Rex 3 are built to withstand extreme conditions. However, each takes a different approach to durability and materials.
The Amazfit T-Rex 3 represents a major leap forward in rugged smartwatch design. Since merging with Zepp, the company has vastly improved its materials and construction, making the T-Rex 3 the most premium and aggressive-looking T-Rex yet. The watch features a stainless steel bezel, which immediately makes it feel more high-end than its predecessor. It has also passed multiple military-grade certifications, ensuring shock, dust, and water resistance.
The T-Rex 3’s display is protected by Gorilla Glass, making it scratch-resistant and more durable, though not completely indestructible. This is a significant improvement, but still not at the same level as Garmin’s premium materials.
On the other hand, Garmin’s Fenix 8 takes durability to another level, offering multiple material choices based on how much you’re willing to spend. You can opt for the standard stainless steel version, which is already premium, or go for more expensive options like a sapphire crystal display and a titanium case. These materials not only make the watch tougher but also lighter, improving overall comfort.
One area where Garmin outshines Amazfit is in water resistance. The Fenix 8 uses conductive buttons, which eliminate the need for mechanical penetration into the case, enhancing waterproofing. This means greater protection in extreme conditions, making the Fenix 8 more reliable for serious outdoor adventurers.
The strap installation method on the Fenix 8 is also superior, ensuring a more secure fit and better durability over time. Garmin’s attention to detail in design and construction solidifies its reputation as a high-end rugged smartwatch brand.
While the Amazfit T-Rex 3 is a huge step up in durability and aesthetics, the Garmin Fenix 8 remains the gold standard in rugged smartwatch build quality. With better materials, improved water resistance, and premium options, the Fenix 8 wins this round.
Displays Specs & Features
The Amazfit T-Rex 3 takes the win in this category. While the Garmin Fenix 8 offers better pixel density and an optional Sapphire Crystal protection for durability, it falls behind in brightness. The Fenix 8 maxes out at around 1,000 nits, whereas the T-Rex 3 reaches an impressive 2,000 nits, making it significantly brighter and easier to read in direct sunlight.
Another standout advantage for Amazfit is its better color optimization, making watch faces look more vibrant and visually appealing. Speaking of watch faces, the T-Rex 3 provides a wider selection of free, easily accessible options, giving users more customization freedom compared to Garmin.
Overall, with a brighter display, better color tuning, and more watch face options, the Amazfit T-Rex 3 wins this round.
Hardware And Specs
The Garmin Fenix 8 and the Amazfit T-Rex 3 are built with very different philosophies, each excelling in certain areas. This is great for consumers, as it fosters competition and innovation, ensuring that both options bring unique strengths to the table.
While specifications alone don’t determine superiority, they do reveal some clear advantages for each smartwatch. For instance, on paper, the Fenix 8’s display should be better, but the T-Rex 3’s color optimization and overall vibrancy make it more visually appealing despite having slightly lower pixel density.
Beyond the display, Garmin Fenix 8 takes the lead in hardware functionality with some important advantages that outdoor and fitness enthusiasts will appreciate.
One standout feature is ANT+ support, allowing the Fenix 8 to connect with third-party health tracking sensors, such as heart rate monitors, cycling power meters, and chest straps. This is a game-changer for serious athletes who rely on precise fitness data.
Another major advantage is the built-in LED torch, which proves to be incredibly useful in everyday scenarios and outdoor adventures. Whether hiking at night, searching for something in the dark, or simply needing a quick light source, this feature is one that you’ll likely use more often than expected.
Additionally, Garmin Fenix 8 features a built-in speaker and microphone, enabling Bluetooth phone call support. This means you can take calls directly from your watch, a feature the Amazfit T-Rex 3 lacks. However, at the time of this comparison, this function is only available for Android users, with no iOS support yet.
Considering these hardware advantages—ANT+ support, a built-in torch, and Bluetooth calling, the Garmin Fenix 8 takes the win in this round. While Amazfit T-Rex 3 is impressive in its own right, the Fenix 8 simply offers more advanced and practical hardware features that enhance real-world usability.
Software & UI
The Garmin Fenix 8 and Amazfit T-Rex 3 come with two very different operating systems, Garmin OS and Zepp OS, each designed with distinct user experiences in mind.
Zepp OS, found on the Amazfit T-Rex 3, is built around RTOS (Real-Time Operating System), making it lightweight, smooth, and highly responsive. It offers fluid animations, intuitive navigation, and a well-organized UI, making it easy to use. One notable advantage is its customization, allowing users to remap buttons and personalize the interface more freely compared to Garmin OS.
On the other hand, Garmin OS, which is likely based on QNX or another RTOS, is highly optimized for button navigation. While some features feel intuitive, certain operations require button presses instead of touch gestures, which can feel less modern at times. However, for workout tracking, this is actually a huge advantage, as touchscreens can become unresponsive when wet or sweaty, making buttons a more reliable option.
A downside of Garmin OS is that it could allow more button remapping, similar to Zepp OS, which provides greater control over user preferences. Despite Garmin offering countless customization options, some aspects of its UI organization feel less intuitive, making navigation slightly more complex than it needs to be.
However, when it comes to tracking workouts and outdoor activities, Garmin OS is second to none. It provides detailed metrics, advanced sports tracking options, and seamless integration with Garmin’s vast ecosystem, making it a top choice for serious athletes and outdoor adventurers.
Ultimately, choosing between the two operating systems comes down to personal preference. Zepp OS feels smoother, more fluid, and more customizable, while Garmin OS prioritizes functionality, reliability, and sports tracking accuracy. Given these factors, this category ends in a tie, as both offer advantages depending on what you prioritize in a smartwatch.
Workout Tracking
The Amazfit T-Rex 3 has made impressive strides, introducing numerous enhancements that make it a strong contender in the fitness tracking world. However, Garmin has been building its fitness ecosystem for years, refining its data analysis, tracking accuracy, and overall experience, making the Fenix 8 almost untouchable in this category.
The T-Rex 3 covers all the essentials, including tracking multiple workout activities, importing routes, and syncing stats with platforms like Strava. It offers reliable tracking for casual users and fitness enthusiasts alike. However, Garmin takes things much further, providing an in-depth, long-term analysis of your performance, revealing insights that you might not even notice right away but can gradually improve your fitness journey.
One of the most talked-about features in Garmin’s ecosystem is VO2 max estimation, which measures the maximum volume of oxygen you can consume per minute, per kilogram of body weight, at peak performance. While its absolute accuracy may be debated, it’s a highly useful metric for tracking improvements in endurance and overall cardiovascular fitness.
Beyond VO2 max, Garmin Connect provides a vast array of detailed workout insights, tracking everything from training load, aerobic and anaerobic effects, recovery time, and advanced performance stats. Wearing the Fenix 8 over an extended period unlocks even more insights and tailored recommendations, which can transform how you train and recover.
Another standout feature of the Fenix 8 is GPS accuracy. While the Amazfit T-Rex 3 performs well, Garmin’s advanced multi-band GPS is noticeably more precise, making it better suited for runners, hikers, and cyclists who require pinpoint tracking accuracy.
To be clear, the Amazfit T-Rex 3 is far from bad at workout tracking—in fact, it’s one of the best in its category. However, Garmin’s Fenix 8 remains the king of fitness tracking, offering an unmatched depth of analysis, accuracy, and long-term data integration. For serious athletes, outdoor adventurers, or those looking for professional-level insights, the Fenix 8 is the clear winner in this round.
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Health Tracking
When it comes to health tracking, the Garmin Fenix 8 and the Amazfit T-Rex 3 offer impressive accuracy and reliability, making them excellent choices for monitoring overall wellness.
Heart rate tracking is well-implemented on both devices, allowing users to customize how frequently measurements are taken. For basic heart rate monitoring, both smartwatches perform similarly well. However, when it comes to more advanced metrics like Heart Rate Variability (HRV), the Fenix 8 takes the lead, offering deeper insights into recovery, stress levels, and fitness adaptation.
A similar trend can be observed with stress tracking, where Garmin’s analytics provide more detailed breakdowns of stress levels throughout the day. The Body Battery feature on the Fenix 8 is another advantage, calculating your energy levels based on activity, sleep, and recovery data—a feature that the T-Rex 3 lacks.
One interesting comparison is temperature tracking. Both watches allow you to monitor temperature trends, but Garmin organizes these metrics into glances, providing a more structured way of visualizing data. However, it’s important to note that wrist-based temperature sensors are highly influenced by external factors, such as wearing gloves or keeping your hand under a blanket, which can cause fluctuations of 3-4°C. The T-Rex 3 seems to have smaller deviations, but both watches require stable conditions for accurate readings.
Where Garmin really pulls ahead is in sleep tracking. Initially, both watches struggled with accuracy, but after several firmware updates, both have significantly improved. However, the Fenix 8 still provides a more refined sleep analysis, including sleep stages, recovery insights, and breathing rate monitoring.
A major distinction between the two is that the Fenix 8 now includes ECG tracking for users in the European region, something not available on the T-Rex 3. This feature provides heart rhythm analysis, which can be a valuable health tool for those monitoring cardiovascular health.
Overall, while both devices offer excellent health tracking, Garmin’s additional insights, better HRV and stress tracking, Body Battery feature, and ECG support give it the clear advantage in this category.
App & Connectivity
The Garmin Fenix 8 and Amazfit T-Rex 3 both allow you to extend their functionality with additional apps, but the way they handle app integration is quite different.
While you won’t find mainstream apps like those available for Apple Watch or Google Pixel Watches, there are still some valuable third-party options that enhance the experience. One of the most useful additions is remote control support for action cameras. Both Garmin and Amazfit offer apps for controlling GoPro and DJI Osmo Action cameras, making them handy companions for adventure enthusiasts.
However, Garmin has a clear advantage when it comes to app development and support. The Garmin Connect IQ ecosystem has been around for years, allowing developers to create and share apps, widgets, and watch faces. This long-standing framework ensures better access to internal storage, enhanced customization, and more robust third-party support.
Additionally, Garmin’s developer community is far more active, with forums, guides, and support systems in place to help users customize and expand their watch’s capabilities. Amazfit’s Zepp OS is catching up, but it still lacks the depth, variety, and developer engagement that Garmin offers.
So while both smartwatches allow third-party app installations, Garmin’s more established platform, larger app selection, and stronger developer support make it the clear winner in this category.
Third-Party Apps:
If you want to expand the features of your smartwatch, you’ll need third-party apps, and both Garmin and Amazfit support them to some extent.
However, Garmin does a much better job here. The Garmin Connect IQ store provides a wider range of third-party applications, including fitness tools, navigation enhancements, and even smart utilities like music apps, live weather tracking, and safety features.
Amazfit’s Zepp OS has a more limited selection of third-party apps, and while it has basic fitness add-ons and customization options, it doesn’t match the depth of Garmin’s ecosystem.
Another big difference is how apps interact with the device. Garmin watches allow deeper system integration, meaning that third-party apps can interact more seamlessly with core smartwatch functions. In contrast, Zepp OS has tighter restrictions, limiting how third-party apps integrate with the system.
So if third-party apps are important to you, Garmin is the better choice due to its larger selection, better system integration, and a more active developer community.
Smartphone App:
The smartphone companion apps for both Garmin and Amazfit serve as hubs for fitness tracking, health metrics, and device customization. However, their user experiences are quite different.
The Amazfit T-Rex 3 uses the Zepp app, which offers a polished, visually appealing interface. Navigation is straightforward, and finding key health metrics is effortless. Users can rearrange sections to prioritize what’s most important to them, making the app highly customizable and user-friendly.
Garmin Connect, on the other hand, is feature-packed but more complex. While it provides significantly more data and offers in-depth analytics, it can feel less polished and harder to navigate. Many users find that accessing key health and fitness insights requires multiple taps, making it less intuitive than the Zepp app.
That being said, Garmin Connect does provide superior depth in tracking and analysis. It’s ideal for serious athletes who want to track every detail of their performance. Zepp, meanwhile, caters more to casual users who want an easy-to-use interface with well-organized stats.
Ultimately, the choice between these apps comes down to personal preference. If you prefer a visually appealing and intuitive app, Zepp is the better option. If you want more data and deeper analytics, Garmin Connect is the superior choice.
In terms of overall usability, Zepp wins for user experience, while Garmin wins for advanced tracking and data depth.
Battery & Charging
Battery life is one of the key differences between the Garmin Fenix 8 and the Amazfit T-Rex 3. Despite the T-Rex 3 having a larger battery capacity, the Fenix 8 is better optimized when it comes to GPS tracking, making it more efficient for long outdoor activities.
However, in most everyday scenarios, the T-Rex 3 outperforms the Fenix 8 in battery longevity, especially when using the Always-On Display. The trade-off is that its display isn’t as bright outdoors, which may impact usability in direct sunlight.
Additionally, the T-Rex 3 charges faster and maintains longer battery life in regular smartwatch usage. If GPS tracking is your main concern, the Fenix 8 wins, but if you prioritize general battery endurance and quicker charging, the T-Rex 3 takes the lead—marking its first well-deserved win in this category.
Pros & 
Cons: Garmin Fenix 8 vs. Amazfit T-Rex 3
Pros (Why You Might Want to Buy These Watches)
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Garmin Fenix 8 Offers Superior Sports & Health Tracking – With advanced GPS tracking, VO2 max estimation, Body Battery insights, and deeper workout analytics, Garmin dominates in fitness tracking. -
Amazfit T-Rex 3 Has Better General Battery Life & Faster Charging – While Fenix 8 lasts longer with GPS tracking, the T-Rex 3 has superior battery life in everyday usage and charges faster. -
Garmin Fenix 8 Has More Accurate Multi-Band GPS – Ideal for runners, hikers, and adventurers, Garmin’s GPS accuracy is significantly better, especially in dense forests or urban environments. -
Amazfit T-Rex 3 Provides Excellent Value for the Price – At a fraction of the cost, the T-Rex 3 delivers a rugged smartwatch experience, making it one of the best-value adventure watches. -
Amazfit T-Rex 3 Has a Brighter & More Vibrant Display – With 2,000 nits of brightness, the T-Rex 3’s AMOLED display is easier to see in bright sunlight, while Garmin’s screen is dimmer but more power-efficient. -
Garmin Fenix 8 Supports ANT+ & Third-Party Health Sensors – Unlike the T-Rex 3, Garmin can connect to external heart rate monitors, cycling sensors, and power meters, making it a better choice for professional athletes.
Cons (Things You Might Not Like)
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Garmin Fenix 8 is Expensive – While it offers premium features, the high price tag makes it a tough sell, especially when the T-Rex 3 delivers a solid experience at a much lower cost. -
T-Rex 3 Lacks Garmin’s Detailed Training & Health Metrics – If you’re an athlete looking for advanced analytics, Garmin’s ecosystem is vastly superior, while T-Rex 3 is more basic in comparison. -
Limited Third-Party Apps on Amazfit – Garmin has a more developed app ecosystem, while Amazfit’s Zepp OS still lacks many third-party integrations and customization options.
Conclusion
At the end of the day, both the Garmin Fenix 8 and the Amazfit T-Rex 3 are outstanding rugged smartwatches, each excelling in different areas.
The Fenix 8 is the better choice for serious athletes and outdoor enthusiasts, thanks to its superior sports tracking, more precise GPS, longer battery life during tracked workouts, and overall better build quality. It also benefits from Garmin’s consistent and high-quality firmware updates, ensuring long-term reliability and performance improvements.
On the other hand, the Amazfit T-Rex 3 offers an incredible value proposition. It outperforms the Fenix 8 in general battery life, has a brighter and more vibrant display, and comes at a much more affordable price. While it may not match Garmin’s level of detailed sports tracking, it delivers a fantastic smartwatch experience for a fraction of the cost.
As mentioned throughout this comparison, the Fenix 8 is not 2.5 times better than the T-Rex 3, despite being significantly more expensive. This makes the Amazfit T-Rex 3 one of the best-value rugged smartwatches of 2025, offering an impressive balance of features, durability, and affordability.
So, which one is the better choice for you? If you want premium features and the best sports tracking, go for the Fenix 8. If you want a reliable, well-built smartwatch with excellent battery life at a more attractive price, the T-Rex 3 is the smarter buy.
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Fenix 8 vs. Amazfit T-Rex 3 Frequently Asked Questions (FAQs)
1. Which smartwatch has better GPS accuracy: Garmin Fenix 8 or Amazfit T-Rex 3?
Garmin Fenix 8 has superior multi-band GPS accuracy, making it more reliable for trail running, hiking, and cycling. The T-Rex 3’s GPS is good but not as precise in challenging environments.
2. Which smartwatch has better battery life?
- For general use: The Amazfit T-Rex 3 lasts longer and charges faster.
- For GPS tracking & workouts: The Garmin Fenix 8 is better optimized and lasts longer during long training sessions.
3. Is the Amazfit T-Rex 3 a good alternative to the Garmin Fenix 8?
Yes, if you want a rugged smartwatch with great battery life and a bright display at a lower cost. However, if you need professional fitness tracking and top-tier GPS accuracy, the Fenix 8 is the better choice.
4. Does the Garmin Fenix 8 justify its high price?
If you’re an athlete, hiker, or someone who needs high-end sports tracking, the Fenix 8 is worth it. But for casual users, the T-Rex 3 provides excellent value without the premium cost.
5. Which smartwatch has better third-party app support?
Garmin Fenix 8 wins in this area, as it supports a wider range of third-party apps via Garmin Connect IQ, while Amazfit T-Rex 3’s Zepp OS has a more limited selection.
6. Can I make calls on either smartwatch?
The Garmin Fenix 8 supports Bluetooth calls on Android (but not iOS yet), while the Amazfit T-Rex 3 does not have calling capabilities.
7. Which smartwatch is better for everyday use?
The Amazfit T-Rex 3 is better for daily wear, thanks to its brighter display, better battery life, and lower price. However, the Garmin Fenix 8 is superior for sports and fitness tracking.
Final Verdict: Which One Should You Choose?
- For serious athletes and professionals, → Buy Now Garmin Fenix 8
- For budget-conscious adventurers, → Buy Now Amazfit T-Rex 3
Both are excellent rugged smartwatches, but which one fits your needs best? Let me know your thoughts! 
