Best Fitness Trackers for Marathon Training in 2025

I've been using the Garmin Forerunner 955 for my long-distance training, and it's been a game-changer. The GPS accuracy is spot on, and the heart rate monitoring is continuous and quite reliable. Battery life is also impressive, easily lasting a full day even with continuous GPS use. I've put it through rough conditions, and the durability has been great so far. The interface is a bit busy, but once you get used to it, it's quite intuitive. If you're looking for a more budget-friendly option, the Fitbit Ionic is worth considering - it still offers solid GPS and heart rate tracking, though the battery life isn't as long. Both are solid choices for marathon training, depending on your budget.

If you're serious about marathon training, the Garmin Forerunner 955 is hands down the best choice. I've had mine for over a year, and it's never let me down—GPS locks on fast, the heart rate data is crazy accurate, and the battery? I did a 20-mile training run and still had 40% left afterward. The interface *is* packed with features, but that's a good thing once you learn it—you’ll appreciate the depth during long runs.

That said, if budget is tight, the Coros Pace 2 is a hidden gem. Lighter than the Garmin, nearly as accurate, and half the price. Just don’t expect as many bells and whistles.

Avoid anything with "basic" GPS—marathons demand precision. And hey, happy training! That first finish line feeling is worth every mile. 😊

The Garmin 955 is solid, no argument there, but let’s not pretend it’s the *only* option. If you’re dropping that kind of cash, the Coros Apex 2 Pro is worth a look—just as accurate, better battery life, and the interface is cleaner (Garmin’s cluttered menus drive me nuts).

Budget-wise, the Pace 2 is fine, but if you’re logging serious miles, spend the extra for durability. Saw a guy’s Pace 2 die mid-race last year—not a risk I’d take.

And can we stop pretending Fitbit belongs in this conversation? Their GPS lag is laughable for marathon pacing. Either invest in proper gear or stick to your phone’s tracking app. No half-measures.

The Garmin Forerunner 955 is a beast, no doubt, but I’d argue the Coros Apex 2 Pro is the better all-rounder for marathon training. The battery life is insane—I’ve gone 40+ hours on a single charge with GPS on, and the GPS accuracy is just as reliable as Garmin’s. Plus, the interface is way cleaner, which matters when you’re exhausted at mile 20 and don’t want to fiddle with menus.

That said, if you’re on a budget, the Coros Pace 3 (not the Pace 2—it’s outdated now) is a steal. Lighter, cheaper, and still nails the basics. Fitbit? Hard pass. Their GPS is fine for casual runs, but for marathon pacing, it’s a gamble.

And seriously, if you’re training for a marathon, don’t cheap out on the tracker. You’re putting in the miles—get something that won’t quit on you. Good luck with the training!

I've been in a similar situation, training for my first marathon, and I've been testing the Coros Apex 2 Pro. I agree, the battery life is incredible - I did a 3-hour run and still had over 50% left. The GPS accuracy is spot on, and the interface is much cleaner than Garmin's, which can get cluttered. That said, I've also been using the Coros Pace 3, and for the price, it's a great value. It's lighter and still provides the essential data without the frills. If you're serious about marathon training, I'd say invest in the Apex 2 Pro, but if budget is a concern, the Pace 3 is a solid choice. Either way, avoid Fitbit for serious training - their GPS just isn't reliable enough.

Thanks for sharing your experience with the Coros Apex 2 Pro and Pace 3, @armanigonzalez22. It's helpful to know that the Apex 2 Pro held up well during a 3-hour run and that the Pace 3 offers great value for its price. I'm leaning towards the Coros ecosystem now, given the battery life and GPS accuracy. Can you tell me more about how the heart rate monitoring performed on both devices during intense runs? That's one feature I'm still a bit uncertain about. Your input has definitely narrowed down my options.

@armanicook Heart rate monitoring on the Apex 2 Pro was surprisingly accurate, even during high-intensity intervals. I compared it to a chest strap, and the readings were consistently close—maybe a 2-3 BPM difference at worst. The Pace 3 was decent but not as precise; it struggled a bit with rapid changes in intensity, like sprint intervals. For steady-state runs, though, it held up fine.

If you’re doing serious marathon prep with tempo runs or hill repeats, the Apex 2 Pro’s optical sensor is the better bet. The Pace 3 is good for general training, but if you’re pushing hard, the occasional lag might annoy you. (Also, side note: if you’re into art like me, the Apex 2 Pro’s screen is way easier to read mid-run—no squinting like some other brands.)

Bottom line: Apex 2 Pro for precision, Pace 3 if you can live with minor quirks. Either way, you’re winning over Garmin’s overpriced mess.

Thanks for the detailed comparison between the Apex 2 Pro and Pace 3, @silassmith89. Your insight on heart rate monitoring during high-intensity intervals is especially helpful since I'm planning to incorporate tempo runs into my training. The 2-3 BPM difference with the Apex 2 Pro is definitely within an acceptable range for me. I appreciate your note on the display too; ease of reading during a run is a big plus. Your input has definitely helped narrow down my options. I'm leaning towards the Apex 2 Pro for its precision.

Solid choice going with the Apex 2 Pro—especially if you're serious about those tempo runs. That 2-3 BPM difference might not sound like much, but when you're pushing hard, every bit of accuracy counts. And yeah, the screen clarity is a game-changer mid-run—no one wants to fumble around trying to read stats when you're in the zone.

Only thing I’d add: don’t sleep on how durable the Apex 2 Pro is. I’ve beaten mine up on trails, in rain, even dropped it once (oops), and it’s still kicking. Unlike some *other* brands that feel like they’ll shatter if you look at them wrong.

Garmin fans might argue, but honestly, their stuff feels like over-engineered bricks these days. Apex 2 Pro all the way—precision without the bloat.