We've tested both in real-world conditions - here's our breakdown of the performance, battery life, and more
When it comes to rugged outdoor smartwatches, Garmin provides two powerhouse options: the premium Fenix 8 and the durable, more affordable Instinct 3.
So, which watch suits your lifestyle best? If you’re an ultra-marathoner monitoring every statistic or a weekend warrior in need of durability and reliability, both watches offer impressive features.
In this real-world comparison, we’ll analyze their performance in everyday use—battery life, GPS accuracy, durability, and smart features—so you can determine which one deserves a place on your wrist.
Check the comprehensive tests and comparisons:
Price and versions
Both the Instinct 3 and the Fenix 8 offer the choice of an AMOLED display or a solar-powered display, with the AMOLED versions increasing the price of both watches.
The Instinct 3 is the more affordable option, with prices beginning at $399.99 for the solar charging model and $449.99 for the AMOLED version. It comes in both 45mm and 50mm sizes.
The Fenix 8 experiences a price increase to $999 and surpasses the $1,000 threshold for some models, making it significantly more expensive, even for the least expensive Fenix 8 variant.
It offers a wider selection of sizes, including 43mm, 47mm, and 51mm for the AMOLED Fenix 8, as well as 47mm and 51mm for the Fenix 8 Solar.
Winner: Garmin Instinct 3 (on price) and Garmin Fenix 8 (on versions)
Specs comparison table
| Garmin Fenix 8 | Garmin Instinct 3 | |
| Case size options | 43mm, 47mm and 51mm | 45mm and 50mm |
| Waterproof rating | 100 metres and 40 metres (diving) | 100 metres |
| AMOLED screen | 1.4-inch , 454 x 454 (47mm) | 1.2-inch , 390 x 390 (45mm) |
| Multi-band GPS | Yes | Yes |
| Full-color maps | Yes | No |
| Navigation and route import | Yes | Yes |
| Battery life | Up to 16 days (47mm) | Up to 18 days (45mm) |
| GPS battery life | 35 hours-17 days (47mm) | 32 hours-16 days (45mm) |
Design, display and build
The Fenix 8 and Instinct 3 certainly offer very different looks, and we’re primarily focusing on the AMOLED versions we tested from these Garmin lines.
With the latest Fenix lineup, you receive the best screen protection that Garmin offers, along with leak-proof buttons that make it suitable for diving. It feels like a really mature watch on the wrist.
On the flip side, there’s the Instinct 3 with its more colorful, playful look that brings to mind Casio’s G-Shock watches and presents an appealing style quite different from the Fenix 8. While it doesn’t offer Sapphire glass or a dive-friendly design, it does match the Fenix with a flashlight—and it’s a nice, bright one too.
If you’re looking for the largest and highest resolution AMOLED display, you’ll find it on the Fenix 8. This isn’t to imply that the color screen on the Instinct 3 is significantly inferior; rather, the Fenix offers a higher quality and larger display.
Additionally, by choosing the Fenix, you’ll benefit from a touchscreen AMOLED, which the Instinct 3 doesn’t have as a method of interacting with the display.
Winner: Garmin Fenix 8
Smart features and OS
The Fenix 8 simply offers more as a smartwatch. It includes all the smartwatch features currently available from Garmin, along with a microphone and speaker for taking calls when paired with your phone via Bluetooth, as well as recording voice notes while you’re on the go.
Additionally, it provides a music player, increased storage, Garmin Pay, and access to the Connect IQ store directly from the watch.
The Instinct 3 is more than adept at delivering your phone notifications, generates helpful Morning Reports summarizing essential stats and insights, supports Garmin Pay, and, although it doesn’t have a built-in music player, it lets you control the music on your phone.
Garmin’s addition of AMOLED screens has prompted tweaks in both software and user interface. It feels reminiscent of the older UI on the Instinct 3, while the changes in the Fenix 8 software are clearly aimed at integrating the more extensive smartwatch features with its sports and activity tracking capabilities.
Winner: Garmin Fenix 8
Battery life
Both watches feature models with a solar charging display, so if you’re looking for the best battery life, those are the versions to choose. Regarding the AMOLED versions, the Fenix 8 should, in general, allow you to avoid reaching for that charger cable a bit longer.
When comparing the 45mm Instinct 3 AMOLED to the 51mm Fenix 8 AMOLED we tested, the Instinct 3 offers up to 18 days of battery life in smartwatch mode and 7 days with the screen continually on.
In contrast, the 51mm Fenix 8 can last up to 29 days in smartwatch mode and 13 days with the screen active 24/7. The larger 50mm Instinct boasts a smartwatch battery life of 24 days and 9 days with the screen constantly activated.
When comparing the 43mm Fenix 8S to the 45mm Instinct 3, the 8S offers up to 10 days in smartwatch mode and 4 days with the screen always on. This increases to 16 days and 7 days if you choose the 47mm Fenix 8.
What we found in our testing is that, unsurprisingly, the larger watch with the bigger battery lasts longer and can run for weeks, even with regular use of the most accurate GPS mode. Keeping that screen on, the Fenix 8 has a better chance of lasting through a week than the Instinct 3, which fell a few days short for us.
If you want significant GPS battery life, you’ll get more of it with the Fenix. In the most accurate mode, the GPS battery life of the Instinct 3 AMOLED ranges from 23 to 30 hours, depending on the size. In contrast, the Fenix 8, with its various model options, offers between 21 and 62 hours in the most accurate GPS mode.
If you consider other features in use, such as continuous monitoring of blood oxygen levels or frequent use of smartwatch functionalities, they will reduce battery performance more quickly on both watches. This is something to remember when you wish to push things further.
Winner: Garmin Fenix 8
Tracking performance
In true Garmin fashion, you receive ample support for the variety of activities and sports you can track both indoors and outdoors.
Both options feature multisport and triathlon modes, along with Garmin’s latest gym-focused muscle maps and workout animations, enhancing their suitability for tracking indoor workouts.
Ultimately, it comes down to their capabilities when you step into the fresh open air. In that regard, the Fenix 8 offers a little extra, which may be a significant advantage for some but not as crucial for others.
The good news is that both models feature Garmin’s latest Multi-Band and SatIQ positioning technology, providing access to arguably one of the best examples of a technology designed to enhance outdoor tracking accuracy in challenging situations like tall buildings and densely wooded areas.
The performance of the Multi-Band GPS on both watches is very good overall, and there isn’t a significant difference between them in that regard.
Where things start to diverge is when you turn to them for mapping and navigation capabilities. The Fenix 8 AMOLED is equipped to display full-color maps, including those for ski resorts.
In addition to turn-by-turn navigation, it also provides Garmin’s helpful ClimbPro ascent planner, NextFork navigation, and roundtrip course creator features for a more enriching mapping and navigation experience.
The Instinct 3 allows users to upload and import routes as well as utilize simpler breadcrumb navigation, which effectively guides you in the right direction. However, you will have to manage without the richer, more detailed maps available on the Fenix 8.
The Fenix 8’s added depth sensor and overall more dive-friendly design also allow you to use it for recreational diving up to 40 meters deep, bringing a host of diving metrics along when you put on a wetsuit.
If you’re looking for more in terms of general wellbeing tracking, the Fenix 8 also features Garmin’s latest Elevate optical sensor, which enables functionalities such as ECG measurements and skin temperature tracking.
The Instinct 3 utilizes the fourth generation of that Elevate sensor and generally provides reliable continuous heart rate data, including heart rate measurements during most exercises as well.
At its core, the Instinct 3 delivers a solid sports tracking experience. However, when you switch to mapping and navigation mode, you’ll discover that the Fenix 8 offers a bit more in that area.
Winner: Garmin Fenix 8
Verdict
Here’s our comparison of the Garmin Instinct 3 and the Fenix 8, highlighting their key differences and similarities. Both are solid performers, but which one should you buy?
Opt for the Garmin Fenix 8 if you’re looking for an AMOLED outdoor watch that offers superior mapping, navigation, and enhanced smartwatch features.
Alternatively, choose the Garmin Instinct 3 if you desire an AMOLED outdoor watch that excels in core sports tracking and offers solid mapping and navigation features at a budget-friendly price.
Also consider: Amazfit T-Rex 3
The T-Rex 3 might not have the same level of smartwatch smarts as Garmin, but it does give you good dual-frequency GNSS and full mapping for considerably less than the Fenix 8 and the Instinct 3.
