GPS Running Watches / Garmin Instinct 3 Solar (45mm) vs Garmin Forerunner 170 (43mm)
Garmin Instinct 3 Solar (45mm) vs Garmin Forerunner 170 (43mm)
Garmin Instinct 3 Solar (45mm)
The honest battery watch: MIP plus solar, but no maps and no music at $400.
Wins overall by 0.4 points
Quick Verdict
The Garmin Instinct 3 Solar (45mm) is the stronger all-round pick, ahead by 0.4 points. The honest battery watch: MIP plus solar, but no maps and no music at $400.
The Garmin Instinct 3 Solar (45mm) and Garmin Forerunner 170 (43mm) are both closely matched GPS Running Watch models, and the Garmin Forerunner 170 (43mm) is $100 cheaper than the Garmin Instinct 3 Solar (45mm) ($299.99 vs $399.99). On GPS Accuracy, the Garmin Instinct 3 Solar (45mm) leads (8.6 vs 6.2/10) — trace quality in cities and under tree cover — multiband L1+L5 hardware plus what independent testers measured in the real world.. On Battery Honesty, the Garmin Instinct 3 Solar (45mm) leads (9.2 vs 7.0/10) — how much of the headline battery claim survives the mode you would actually train in: all-systems plus multiband, always-on display, music playing. The number on the box is almost always the slowest, least accurate mode.. On Display, the Garmin Forerunner 170 (43mm) leads (8.4 vs 6.4/10) — brightness, resolution and daylight readability, weighing AMOLED sharpness against MIP's always-on-for-free behaviour.. Overall, the Garmin Instinct 3 Solar (45mm) scores 7.2/10 across our 8 scoring categories versus 6.8/10 for the Garmin Forerunner 170 (43mm). Below, we break down the full spec sheet, category-by-category scores, and exactly who should buy which one.
Side-by-Side Comparison
| Spec | Garmin Instinct 3 Solar (45mm) | Garmin Forerunner 170 (43mm) |
|---|---|---|
| Price | $399.99 | $299.99 |
| Release Year | 2025 | 2026 |
| Display | Monochrome 176x176 transflective MIP, always-on by design, no touchscreen — readable in direct sun and costs almost nothing to leave on | 1.2-in 390x390 AMOLED touchscreen, optional always-on |
| Smartwatch Battery ( days) | 28✓ | 10 |
| Always-On Display Cost | There is no always-on penalty: MIP is always on. With 3 h/day at 50,000 lux the solar lens makes smartwatch mode effectively unlimited and stretches multiband GPS from 24 h to about 60 h. | 4 days with always-on display — the headline 10-day figure assumes the screen is off between glances |
| Battery, Single-Band GPS ( h) | Sources conflict: 40 h (the5krunner spec sheet, 45 mm, no solar) vs 50 h (garminrumors spec wiki, lower bound of its 45/50 mm range) | 20 |
| Battery, Multiband GPS ( h) | 24 | No multiband mode exists on this watch; all-systems (L1 only) runs 14 h |
| GNSS Bands | Multi-band dual-frequency L1+L5 (GPS, GLONASS, Galileo, BeiDou, QZSS) with SatIQ — DC Rainmaker confirms every Instinct 3 got multiband | Single-band L1 multi-GNSS (GPS, GLONASS, Galileo, BeiDou, QZSS). No L5/dual-frequency — DC Rainmaker's hands-on and the garminrumors spec wiki both confirm this; the5krunner's spec page loosely calls it 'multi-frequency', which is wrong. Multiband starts at the Forerunner 570. |
| Onboard Maps | None. No offline maps and no route storage to speak of — DC Rainmaker called shipping a $400-plus outdoor watch without maps 'pretty hard to swallow'. | None. Breadcrumb course-following only — no TopoActive maps, no turn-by-turn, no ClimbPro. |
| Music Storage | None. No music storage, no streaming, no Wi-Fi — phone music control only. | Only on the $349.99 Forerunner 170 Music: 4 GB with offline Spotify, Amazon Music and Deezer. The $299.99 base model reviewed here has no music storage and no Wi-Fi. |
| Training Platform & Subscription | Garmin Connect is free and every core training metric — Training Readiness, Training Load, Training Status, HRV Status, Body Battery, recovery time — is Firstbeat-derived and free on the watch (Garmin bought Firstbeat in 2020). Connect+ is $6.99/mo or $69.99/yr and adds only AI wellness prompts, 3D maps, Trails+ routing, extra badges and nutrition logging — nothing a training plan depends on. | Garmin Connect is free and every core training metric — Training Readiness, Training Load, Training Status, HRV Status, Body Battery, recovery time — is Firstbeat-derived and free on the watch (Garmin bought Firstbeat in 2020). Connect+ is $6.99/mo or $69.99/yr and adds only AI wellness prompts, 3D maps, Trails+ routing, extra badges and nutrition logging — nothing a training plan depends on. |
| External Sensor Support | ANT+ and Bluetooth chest straps, pods and power meters | Pairs with both ANT+ and Bluetooth chest straps, footpods and Stryd — the cheap fix for wrist-HR interval errors |
| Data Export | Full .FIT file access over USB/MTP plus free automatic sync to Strava, TrainingPeaks, Runalyze, intervals.icu and others through Garmin Connect. | Full .FIT file access over USB/MTP plus free automatic sync to Strava, TrainingPeaks, Runalyze, intervals.icu and others through Garmin Connect. |
| Warranty | 12 months | 12 months |
| Colors | Black | Black / Amp Yellow |
Category Scores
GPS Accuracy
The Garmin Instinct 3 Solar (45mm) leads clearly here, 8.6 against 6.2 — a 2.4-point margin on trace quality in cities and under tree cover — multiband L1+L5 hardware plus what independent testers measured in the real world.. If that is what you are buying for, the Garmin Forerunner 170 (43mm) does not close the gap elsewhere.
Battery Honesty
The Garmin Instinct 3 Solar (45mm) leads clearly here, 9.2 against 7.0 — a 2.2-point margin on how much of the headline battery claim survives the mode you would actually train in: all-systems plus multiband, always-on display, music playing. The number on the box is almost always the slowest, least accurate mode.. If that is what you are buying for, the Garmin Forerunner 170 (43mm) does not close the gap elsewhere.
Training & Recovery
The Garmin Instinct 3 Solar (45mm) is marginally ahead, 7.8 to 7.4. A gap this small rarely decides a purchase on its own, though it counts if depth of load, readiness and recovery analysis, and how much of it is free rather than gated behind a subscription or an extra chest strap. is your priority.
Heart Rate
The Garmin Instinct 3 Solar (45mm) is marginally ahead, 7.2 to 6.8. A gap this small rarely decides a purchase on its own, though it counts if optical wrist accuracy during intervals and burst efforts, and whether the watch pairs with ANT+ and/or Bluetooth chest straps as a fix. is your priority.
Display
The Garmin Forerunner 170 (43mm) leads clearly here, 8.4 against 6.4 — a 2.0-point margin on brightness, resolution and daylight readability, weighing AMOLED sharpness against MIP's always-on-for-free behaviour.. If that is what you are buying for, the Garmin Instinct 3 Solar (45mm) does not close the gap elsewhere.
Build & Comfort
The Garmin Instinct 3 Solar (45mm) and Garmin Forerunner 170 (43mm) are level here, at 8.2/10 each. case materials, lens (sapphire vs glass), weight on the wrist and durability ratings. is not what separates these two — look to the categories where the scores diverge.
Value
The Garmin Forerunner 170 (43mm) leads clearly here, 7.8 against 7.0 — a 0.8-point margin on what the watch delivers per dollar against everything else in the comparison at the moment of purchase.. If that is what you are buying for, the Garmin Instinct 3 Solar (45mm) does not close the gap elsewhere.
Best For
Choose the Garmin Instinct 3 Solar (45mm) if…
- • GPS Accuracy matters most to you — the Garmin Instinct 3 Solar (45mm) scores 8.6/10 here (trace quality in cities and under tree cover — multiband L1+L5 hardware plus what independent testers measured in the real world.).
- • Battery Honesty matters most to you — the Garmin Instinct 3 Solar (45mm) scores 9.2/10 here (how much of the headline battery claim survives the mode you would actually train in: all-systems plus multiband, always-on display, music playing. The number on the box is almost always the slowest, least accurate mode.).
- • Heart Rate matters most to you — the Garmin Instinct 3 Solar (45mm) scores 7.2/10 here (optical wrist accuracy during intervals and burst efforts, and whether the watch pairs with ANT+ and/or Bluetooth chest straps as a fix.).
- • Your main use case is trail-ultra or long-battery.
Choose the Garmin Forerunner 170 (43mm) if…
- • Display matters most to you — the Garmin Forerunner 170 (43mm) scores 8.4/10 here (brightness, resolution and daylight readability, weighing AMOLED sharpness against MIP's always-on-for-free behaviour.).
- • Value matters most to you — the Garmin Forerunner 170 (43mm) scores 7.8/10 here (what the watch delivers per dollar against everything else in the comparison at the moment of purchase.).
- • You want to spend less — it's $100 cheaper.
- • Your main use case is road-running or triathlon.
Pros & Cons
Garmin Instinct 3 Solar (45mm)
Pros
- +MIP plus solar is the one combination here where the headline battery figure is close to what you actually get
- +Multi-band L1+L5 GNSS at $399.99, in a 10 ATM, MIL-STD-810 tested case
- +Solar can push smartwatch mode to effectively unlimited and multiband GPS from 24 h to about 60 h
- +No always-on display penalty at all — the screen is transflective and permanently visible
Cons
- −No offline maps and no music storage, on a watch that costs as much as an Amazfit T-Rex 3 Pro that has both
- −Storage is the reason: sources conflict badly — the garminrumors wiki says 32 GB while DC Rainmaker and Tom's Guide report roughly 120-128 MB on Solar models, too small even to hold a firmware update alongside courses
- −Multiband drops runtime to 24 h without sun — a quarter of the 100 h Max Battery GPS headline
- −Older Elevate Gen 4 optical HR sensor, not the Gen 5 in cheaper Garmins
- −Monochrome 176x176 MIP screen looks a decade old next to every AMOLED rival, and there is no touchscreen
Garmin Forerunner 170 (43mm)
Pros
- +Adds a barometer, gyroscope, wrist running power, Training Readiness and open-water swimming over the Forerunner 165 it replaces
- +Every training and recovery metric is free — Connect+ at $6.99/mo adds nothing a runner's plan depends on
- +Pairs with ANT+ and Bluetooth chest straps, so $60 of strap fixes the wrist sensor for intervals
- +20 h of GPS-only battery covers a road marathon several times over
Cons
- −Single-band L1 GNSS only — in city streets or under canopy the trace drifts, and multiband costs $250 more (Forerunner 570)
- −No multisport/triathlon mode at all, so it cannot record a triathlon; DC Rainmaker flags this as the headline omission
- −No maps of any kind, and no turn-by-turn — breadcrumbs only
- −Music is a $50 upcharge: the base model has zero song storage and no Wi-Fi
- −The 10-day smartwatch claim drops to 4 days the moment you enable the always-on display
Shop by Need
FAQs
Is the Garmin Instinct 3 Solar (45mm) or Garmin Forerunner 170 (43mm) better overall?+
Based on our 8-category scoring, the Garmin Instinct 3 Solar (45mm) comes out ahead overall. See the full breakdown in the scores section above — the right pick still depends on which categories matter most for your use case.
Which is better for GPS Accuracy, the Garmin Instinct 3 Solar (45mm) or the Garmin Forerunner 170 (43mm)?+
The Garmin Instinct 3 Solar (45mm) scores higher on GPS Accuracy (8.6/10 vs 6.2/10) — trace quality in cities and under tree cover — multiband L1+L5 hardware plus what independent testers measured in the real world..
Which is better for Battery Honesty, the Garmin Instinct 3 Solar (45mm) or the Garmin Forerunner 170 (43mm)?+
The Garmin Instinct 3 Solar (45mm) scores higher on Battery Honesty (9.2/10 vs 7.0/10) — how much of the headline battery claim survives the mode you would actually train in: all-systems plus multiband, always-on display, music playing. The number on the box is almost always the slowest, least accurate mode..
Which is better for Display, the Garmin Instinct 3 Solar (45mm) or the Garmin Forerunner 170 (43mm)?+
The Garmin Forerunner 170 (43mm) scores higher on Display (8.4/10 vs 6.4/10) — brightness, resolution and daylight readability, weighing AMOLED sharpness against MIP's always-on-for-free behaviour..
Which is better for Value, the Garmin Instinct 3 Solar (45mm) or the Garmin Forerunner 170 (43mm)?+
The Garmin Forerunner 170 (43mm) scores higher on Value (7.8/10 vs 7.0/10) — what the watch delivers per dollar against everything else in the comparison at the moment of purchase..
Is the Garmin Instinct 3 Solar (45mm) worth the price difference over the Garmin Forerunner 170 (43mm)?+
The Garmin Forerunner 170 (43mm) is the cheaper option at $299.99 versus $399.99. Whether the pricier model is "worth it" depends on how much you value its lead in GPS Accuracy.
Which is better suited to my use case?+
The Garmin Instinct 3 Solar (45mm) is the better fit if you mainly care about trail-ultra or long-battery. The Garmin Forerunner 170 (43mm) is the better fit for road-running or triathlon.
What's the warranty on the Garmin Instinct 3 Solar (45mm) vs the Garmin Forerunner 170 (43mm)?+
The Garmin Instinct 3 Solar (45mm) ships with a 12-month warranty; the Garmin Forerunner 170 (43mm) ships with a 12-month warranty. Always confirm current terms on the manufacturer's site before buying.
Should I wait for the next model instead of buying either of these?+
If either model is more than two years old, a successor may be close — check the "Latest Model" link on each product page. Otherwise, both are current, well-supported options and there's no strong reason to wait.
Cheaper Option
COROS PACE 4 (silicone band) — $249.00
Premium Option
COROS APEX 4 (42mm) — $429.00
Specifications and prices for both products last verified . Scores are calculated from published specifications — see how we compare products.