The Garmin Fenix 8 GPS Watch is a great choice for ultra runners and trail runners, offering the durability and features needed for extreme endurance athletes and adventurers.
With advanced strength training features, it doubles as a powerful tool for cross-training, ensuring runners can build the strength and resilience required to tackle demanding terrains.
Its premium build includes enhanced GPS accuracy, which is crucial for long runs in remote or rugged environments. Garmin has integrated additional ultra-running-specific features—like improved battery life, dynamic pacing tools, an essential companion for those pushing their limits on the trails.
As well as all the great the navigation, training and fitness features, the Garmin Fenix 8 watches also come with many smart features such as Garmin Pay, add music from your favourite music apps such as Spotify, Deezer etc, view messages alerts and phone notification on your watch and there is even have a built-in flashlight which I have found very useful when needing to change batteries in my Head torch.
Within the range of Garmin Fenix 8 watches there are several different sizes available and the option of either the bright vibrant Amoled screen or the Solar MIP screens that although not as bright as the Amoled screens they are especially good for viewing in the outdoors and give increased battery life with the solar screen.
In the information below we are covering more the Navigational Features of the watch for when using out on the trails on ultra events etc.
Battery Performance
At the Outdoor GPS Shop we have been testing for the last few months the middle-sized Garmin Fenix 8 – 47mm Amoled version and have been very impressed.
We tend to use the watch with the all Satellites setting turned on and the screen set to not always on, we have been achieving a battery life figure of around 35 hours.
For events that are going to be longer than 35 hours or where you do not have the options for charging, we would recommend looking at the Garmin Fenix 8 Solar options.
As an example the Garmin Fenix 8 47mm Solar watch can achieve approximately 48 hours with all satellites recording and with solar can potentially go to 59 hours.
The best battery comes from the Garmin Fenix 8 – 51mm solar version which can achieve with All Satellite Systems up to 68 hours or 92 hours with solar.
Also when taking part in multi day events where you might come into a checkpoint for a rest there is a great feature on the Garmin Fenix 8 watches when using the ultra-run rest feature, where from a single button press you can pause your recording and you screen will display your rest time but keep the activity timer going and a simple button press to re-start, this helps with battery as turns of GPS recording whilst you rest.
Manufactures Battery figures below for the Garmin Fenix 8 – 47m Amoled version that we have been testing:
Smartwatch: Up to 16 days (7 days always-on)
Battery saver watch mode: Up to 23 days
GPS Only: Up to 47 hours (37 hours always-on)
All Satellite Systems: Up to 38 hours (30 hours always-on)
All Satellite Systems + Multi-band: Up to 35 hours (28 hours always-on)*
All Satellite Systems + Music: Up to 10 hours
Max Battery GPS: Up to 81 hours
Expedition GPS: Up to 17 days
*Assuming typical use with SatIQ technology
Satellite Accuracy and Lock Speed: Garmin Fenix 8 Performance
Over the last few months, I’ve thoroughly tested our Garmin Fenix 8 - 47mm Amoled during a series of hikes and an off-road trail marathon. Its satellite accuracy and lock speed have consistently impressed me, making it a reliable companion for trail running and outdoor adventures.
Real-World Testing: Off-Road Trail Marathon
During my first test—a trail marathon through fairly dense forested areas—our Garmin Fenix 8 – 47mm Amoled that I was using alongside the Coros Vertix 2s watch that I was also testing performed very well and it was hard to tell the two watches apart.
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Mile Marker Precision:
I set 1-mile distance alerts, and the watch accurately aligned with the event’s mile markers almost perfectly. By the end of the marathon, the watch recorded a total distance of 26.28 miles, showcasing minimal drift even in challenging environments like tight forest corners.
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Tracking Accuracy:
Reviewing the recorded route, the tracking was precise, with only slight deviations in areas with tight turns—a common challenge for GPS devices in dense tree cover.
Quick Satellite Lock
One of the standout features of the Garmin Fenix 8 - 47mm Amoled was its speed in locking onto satellites:
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All Systems On Mode:
Using this mode, the watch consistently locked onto satellites in just 8 - 10 seconds after starting an activity. This speed is ideal for runners and hikers who want to get moving without delays.
Why Satellite Accuracy Matters
For runners, hikers, and adventurers, precise GPS tracking is essential for route planning, distance measurement, and ensuring you stay on course. The Garmin Fenix 8 - 47mm Amoled quick satellite lock and high accuracy make it a standout choice for anyone navigating challenging terrains or dense forests.
Vibrant Amoled Screen – especially good in low light conditions but also great in sunlight
The Garmin Fenix 8 - 47mm Amoled features a good sized 1.4-inch display with an impressive resolution of 454 x 454, due to the new styling of the thinner outer bezel the 47mm version has the same screen size as the larger 51mm model.
The Garmin Fenix 8 - 47mm Amoled with its bright, crisp AMOLED display is a significant upgrade for outdoor enthusiasts, especially ultra runners and adventurers. A sunlight-readable screen is a game-changer for visibility during long runs or treks in bright, exposed environments. The AMOLED technology not only ensures better clarity but likely enhances the experience of using maps, metrics, and navigation features on the go.
For trail runners, this means no more squinting or struggling to read your watch during a midday ascent. Plus, the Garmin Fenix 8 balances AMOLED with excellent battery optimisation, so this feature doesn't come at the cost of endurance.
I really liked the vibrant colours of screen, especially when viewing the maps, and the data box fields were clear to view whilst running the trails that I have been on.
Also there is a new option called text size where you can adjust the text size up or down to suit for how text is displayed on the menu’s and widget screens.
Flexible Data Box Layouts
The Garmin Fenix 8 watches have extensive customization for activity data screens, allowing you to tailor the layout to your preferences:
- Choose between 1, 2, 3, 4, 5, 6 or 8 data box fields per screen.
- You can create up to 17 data box pages, enabling you to organize and view all the information you need for your activity.
(We tend to as well as the map screen for navigation have around 3 or 4 data box pages maximum which works well for us, but it will depend on what information you want to see personally and the number of fields that you create per page.
Designed for Accessibility
For users who wear reading glasses, like me, we foind the 1, 2 or 3-data box layout is particularly helpful as the data is nice and large, the clear fonts on the Amoled screen are a great help to.
Below are some examples of the data box layouts that we have used on our Garmin Fenix 8 - 47mm Amoled . These layouts showcase how customizable and clear the screens are, even in challenging conditions like bright sunlight or during fast-paced activities.
The Garmin Connect mobile App makes it incredibly simple to customize your activities and adjust the data box screen layouts to suit your preferences. Whether you’re preparing for a trail run, hike, or ultra race, the app provides a user-friendly interface to tailor your watch settings
Clear route navigation line, off course alerts, turn indication & track back function
With ultra events like the Montane Spine Winter & Montane Spine summer race and the Montane Spine Challenger events the organisers will provide you with GPX files of the route which can be loaded very easily onto your Garmin Fenix 8 Watch either using the Garmin Connect Mobile App or Explore App & a Bluetooth connection to your watch.
The Garmin Fenix 8 watches in the UK come preloaded with Garmin’s European Topo Active mapping and can display several types of Garmin® map data, including topographical contours, nearby points of interest, ski resort maps, and golf courses. You can use the Map Manager directly on the watch with Wifi to download additional maps or manage map storage.
(We do find that if you do have a computer Garmin Express software is much quicker for updating & downloading new maps to your watch although it can be done via wifi on the watch directly)
Pros and Cons of the Fenix 8 Mapping
Having the options to have maps for all of Europe is great but here are some limitations:
· The maps are less detailed than the typical Hiking / Trail running maps that we use from the likes of Ordnance Survey Maps that we use in the UK.
· Although the Garmin Fenix 8 with the Amoled screen that we have been testing is bright & vibrant for more complex navigation the larger screen of a handheld GPS device with more detailed OS mapping can be better.
We find having both a Handheld GPS device and a Watch work well, on my first Montane Spine race attempt I did find that I used my GPS watch for 80% of the navigation but did use the handheld device on some more difficult navigation situations.
However, there are also key advantages:
· The pre-loaded Topo Active maps are Routable with points of interest searches available, I have found this more useful for my road cycling as not all trails are marked on the maps for your offroad activities as compared to our more detailed OS maps, but for cycling this is a great feature where you can search for a place, point of interest etc and the watch will automatically navigate you there with Turn by Turn alerts, when you get close to junctions a large clear turn alert screen as shown below is displayed.
· - Garmin Fenix 8 Watches are also compatible with a number of Open Source maps that are readily available hence giving you some extra flexibility of installing Mapping from other sources.
- The Topo Active maps are true digital vector layered maps hence when you zoom in close, they keep their sharpness & clarity.
User-Friendly Navigation Features
The off-course alerts are highly effective. If you stray off your route, this feature is particularly useful for trail runners, hikers and cyclists in unfamiliar terrain.
- Off Course Alert: Triggers when you deviate significantly from your planned route.
- On Course Alert: Appears when you’ve successfully returned to the route.
- Navigation Options: You can use the Compass Page or Map Page to realign yourself with your route.
The Garmin Fenix 8 also offers turn-by-turn navigation alerts to assist you during your activities when navigating a Route, when you import a GPX route into the Garmin Connect Mobile App there is a great option to Turn on Turn Alerts and as long as you also have them on your watch turned on you can received audible & visual alerts advising you when turns come up which we have found really useful.
The magenta route line that is displayed showing your course to follow is nice and clear and also has white arrow indicators to help you with direction of travel along your route.
As well as button control the Fenix 8 watches also have a very responsive touch screen, if preferred you can just turn on touch screen function for when using the map screen, the touchscreen allows you to move around the map and you also have zoom in and out icons on the touch screen or you can use buttons for this.
If you have the map detail set to high we did find that the maps can render a bit slow if you try and move a distance away but once you are zoomed into your desired level they move fine during Trail running, Hiking, Mountain biking etc as you move at speed.
We have found the touchscreen very fast & responsive when moving through menus, although when wearing gloves we would use the button control.
When recording a route, you can at any time goto the navigation screen and select the option to trackback following your exact breadcrumb trail back to the starting point.
Elevation Data, Climbpro & up head Checkpoints information.
On your Garmin Fenix 8 watch at any time you can view an elevation graph of your route that you have loaded, but a feature we really like is that you can look ahead at graphs for all your individual Ascents and Descents coming up and using Climbpro function you can automatically have your climbs appear as you approach them.
Garmin ClimbPro Feature: Manage Your Effort on Climbs
The Garmin ClimbPro feature helps athletes manage their effort during ascents by providing detailed climb information in real-time. Available on select Garmin devices, ClimbPro analyses preloaded courses and identifies significant climbs, giving users insights such as gradient, distance, and elevation gain. This feature is particularly useful for cyclists, trail runners, and hikers looking to optimise their performance on hilly routes.
Key Features of Garmin ClimbPro:
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Real-Time Climb Data: View upcoming climb details, including distance, elevation gain, and gradient.
Up ahead Checkpoint information
On ultra events that we have taken part in we have used the Garmin connect app to add checkpoints / aid stations etc to our route before transferring to the GPS watch.
With the Garmin fenix 8 Up Ahead feature, your navigation experience is enhanced when navigating a course, this feature adds a dedicated data screen to your activity, presenting upcoming course points in a rolling list format. This allows you to anticipate important locations such as aid stations, trail forks, or points of interest, helping you manage your effort and strategy effectively.
Key Aspects of the Up Ahead Feature:
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Real-Time Updates: As you progress along your course, the Up Ahead screen dynamically updates to show the next set of course points, ensuring you have timely information about upcoming segments.
As well as Route navigation the Garmin Fenix 8 watches also have an electronic compass & barometric altimeter.
There is a great option with the Garmi Fenix 8 watches to add Hot keys, this allows either a single long press of one key or two keys together to access screens or widgets of your choice, we like to set one up to display our current grid reference which for the UK we set to BNG to give us an Ordnance Survey Grid Reference to cross refer with our paper Ordnance Survey map if required.
Tough and Robust Construction: Garmin Fenix 8
The Garmin Fenix 8 is built for durability, all of the models that we stock have the very tough Sapphire screen and come with a Titanium Bezel.
The Fenix Watches are tested to the following Water & temperatures ratings:
Water rating
10 ATM
4 ATM Dive (Designed to comply with CSN EN 13319)
Operating and storage temperature range
From -20º to 45ºC (from -4º to 113ºF)
Underwater operating temperature range
From 0° to 40°C (from 32° to 104°F)
USB charging temperature range
From 0º to 45ºC (from 32º to 113ºF)
Solar charging temperature range
From -20° to 80°C (from -4° to 176°F)
An example below of some of the Widget screens such as weather data & Sunset / Sunrise screens.
Conclusion: Why the Garmin Fenix 8 Stands Out
After several months of using the Garmin Fenix 8 , including hikes, a marathon, and gym HIIT sessions, I’m thoroughly impressed by its performance.
I really like the bright vibrant Amoled screen making it so clear to view data screens and the coloured map, the led flashlight has been more useful than I thought it would be and has been used many times when changing batteries in my head torch and around the house.
If you are looking for not just a GPS watch for your navigation help and lots of fitness metrics but also a fully loaded smart watch all in on this watch is a great choice.
The Garmin fenix 8 continues to set the benchmark for premium multisport GPS smartwatches, combining robust durability, advanced navigation, and cutting-edge training features. Designed for outdoor adventurers, endurance athletes, and fitness enthusiasts, it offers unmatched versatility for a wide range of activities.
Key Reasons the Garmin fenix 8 Excels:
Tough & Durable Construction – Built with premium materials, including sapphire glass and titanium options, ensuring rugged resilience for extreme conditions.
Advanced Mapping & Navigation – Features routable maps, turn-by-turn navigation, and the ClimbPro tool, providing detailed elevation and gradient insights for cyclists, hikers, and trail runners.
Innovative Performance Metrics – Offers VO2 max, stamina tracking, real-time endurance insights, and recovery recommendations, making it an essential training companion.
Up Ahead Feature – Displays important course points in a rolling list, allowing users to anticipate aid stations, checkpoints, and key locations during an activity.
Comprehensive Health & Fitness Tracking – Includes heart rate monitoring, SpO2 tracking, sleep analysis, and stress tracking, ensuring a holistic approach to wellness.
Excellent Battery Life – We have been using the Amoled model and have been happy with the battery for our events but you for increased battery you can opt for the solar charging mip screen options, which will provide a longer battery life, essential for multi-day adventures and endurance events.
Highly Customisable & Smart Features – Compatible with Garmin Connect, Strava, Komoot, and other third-party apps, while also offering smart notifications, music storage, and Garmin Pay.
Out on the trails and when you come into villages etc I have found Garmin Pay very useful for those well-earned coffee stops etc negating the need for carrying my bank cards.
Final Verdict: Who Should Buy the Garmin fēnix 8?
The Garmin fenix 8 is a great choice for anyone seeking a high-performance GPS smartwatch with durability, navigation capabilities, and fitness tracking features. Whether you’re a runner, cyclist, mountaineer, or triathlete, this watch provides the tools you need to train smarter and explore further.
