Garmin Instinct 3 Solar Review: Battery Life Tested

Updated & Reviewed August 2026

• Reliability
• Video
• Strengths
• Battery
• Hardware
• Navigation
• inReach

The Garmin for hikers who want to stop thinking about battery and don’t need maps. Runs 75 to 150 hours of GPS on solar, depending on sun.

Garmin built this around solar charging and physical buttons instead of smartwatch features, and after weeks on the trail it does exactly that without fuss. The catch is no onboard maps and an interface less polished than the Fenix. If you want maps on your wrist, the Enduro 3 is worth the extra money.

Reliability

The Instinct has gone through several firmware releases since I first tested it, and some introduced new bugs. I’d highly recommend checking Garmin’s Instinct user forum to see what the latest state of the firmware is before buying.

The core strengths and weaknesses that I cover below stay the same.

Video

Here’s what it looks like to use the Garmin Instinct 3 Solar hiking on a section of the PCT by Palm Springs.

Strengths

The Instinct 3 Solar is built for people who want something dependable in heat, cold, rain, and sweat, not a tiny smartphone on your wrist. What it does well on trail:

• Check distance or pace without reaching for your phone.
• Battery lasts far longer than any AMOLED watch.
• Buttons work in rain, cold, and with sweaty or dirty fingers.
• Basic navigation with off-trail alerts.
• Nothing about it feels delicate or fussy.

Battery

After a few weeks of mixed terrain, varied sunlight, and normal trail use, here’s what I actually saw:

• Mixed canopy, GPS only: ~75 hours. On typical forested trails dipping in and out of shade. With navigation running, battery barely moves. One of the few watches where you can track multiple days in a row without topping up.
• Full sun above tree line: ~150 hours. This is where solar earns its keep. If your wrist is in direct sun for long stretches, the battery climbs instead of drops. I repeatedly ended days with more charge than I started.
• Smartwatch mode, no GPS: ~40 days or less With moderate sun, like hiking outside every day, this becomes “charge it once and forget about it for a month or two.” Without sun and Bluetooth on, it’s more like 7-9 days.
• Charge from empty: ~2 hours. Quick wall charge, no special cable quirks.

Battery Saver mode charges faster in low sun by shutting off power-hungry sensors. You can customize it to only disable what you don’t need, which is useful for squeezing more out of solar.

Hardware

• The classic five-button layout has no touchscreen, and on trail that’s the right call. No swiping with wet fingers, no hoping the screen reads your touch in the cold, no fighting the interface with gloves on. Buttons are clicky, predictable, and always work.
• The 50mm Solar has a tough, slightly retro look, close to a modern G-Shock. The plastic case is durable and needs less care than a Fenix. The buttons take a bit more pressure than the Fenix, but you stop noticing after a few presses. When you’re using poles or dealing with rain, buttons over touchscreen isn’t even a question.

Navigation

• Tracking a hike is straightforward: upper-right button, choose Hike, wait for GPS lock, start walking. Data screens are customizable with the usual Garmin fields: pace, distance, elevation, respiration, sunset, temperature.
• GPS accuracy has been solid. The watch offers GPS, All Satellites, and Multi-Band, but Multi-Band burns more battery. For a long thru-hike where you want to minimize charging, GPS-only is the right setting.
• No maps on the Instinct 3 Solar, but you can load a course and track whether you’re on the line or drifting off it. Breadcrumb routing, off-course alerts, turn prompts, and TracBack are all there. For most hikers, that’s enough. For full topo maps, pair with the free Garmin Explore app on your phone.
• Getting routes onto the watch is easy: build a course in Garmin Connect, import a GPX file, or use AllTrails’ “Send to Garmin” button. Long trails like the PCT work fine loaded in sections from a GPX. Loading an entire thru-hike at once will overwhelm it, but the same is true of the Fenix and Enduro.

inReach

This is one of the strongest reasons to pick the Instinct over a cheaper smartwatch. When paired with an inReach, you can handle almost everything from your wrist:

• Trigger SOS
• Read incoming messages
• Send presets or quick replies
• Start and stop satellite tracking
• See message confirmations without pulling out the device

If your inReach is clipped to the back of your pack, handling all of this from the watch is a real upgrade. No stopping to unclip, unzip a pocket, or fumble with tiny buttons. In an emergency or just at the end of a long day, wrist-based control is faster and easy. And because the Instinct uses buttons, the whole setup keeps working in rain, cold, or with gloves on.

Next Steps