Best Running Watches For Marathons

Running Watches

The Truth About Choosing a Marathon Watch (It’s Not What You Think)

Alright, so you’re training for a marathon and you’re looking at watches. You see a Garmin Forerunner 265, an Apple Watch Ultra, a Coros Apex, and your brain kind of breaks trying to figure out which one you actually need.

Here’s what I realized after talking to dozens of marathon runners: most watch guides miss the real differentiator.

They’ll tell you “this watch has great GPS” or “this one has the best battery life.” But here’s what actually matters when you’re grinding through 16-week marathon training:

Will this watch help ME train better based on HOW I’M TRAINING?

So I organized this guide differently. Instead of watch-by-watch, we’re doing this by your actual training profile: your weekly mileage and your marathon goal.

If you are looking for the right running shoes for marathon training check out our reviews afterwards.

The Casual Marathoner (20-25 mpw, Sub-5 Goal)

The Serious Amateur (25-35 mpw, Sub-4 Goal)

focused marathon runners competing in a street

The Dedicated Runner (35-50 mpw, Sub-3 Goal)

Jump to: Marathon Watches | Real Differences | App Ecosystem | Honest FAQ

Quick Top Marathon Watch Picks

🏃 The Casual Marathoner

20-25 mpw | Sub-5 Goal

Running 3-4 times per week. Your “long run” is the centerpiece. You follow a basic training plan.

Best Watch

Garmin Forerunner 55 $199

20 hr GPS battery • Monochrome display • Budget-friendly

🎯 The Serious Amateur

25-35 mpw | Sub-4 Goal

Running 4-5 times per week. Structured plan with a coach. Quality workouts matter.

Best Watch

Garmin Forerunner 165 $299

19 hr GPS • AMOLED display • Body Battery metrics

⚡ The Dedicated Runner

35-50 mpw | Sub-3 Goal

Elite amateur territory. 6-7 runs per week. Multiple quality workouts. Probably have a coach.

Best Watch

Garmin Forerunner 265 $399

20 hr GPS • Running Dynamics • Lactate Threshold test

🏆 The Elite/Ultra Runner

50+ mpw | Sub-2:50 or Ultra

Chasing elite times or running ultramarathons. Advanced recovery metrics matter. Multi-sport training.

Best Watch

Garmin Forerunner 570 $549

18 hr GPS • Multi-band accuracy • Full training suite

WEEKLY MILEAGE & TRAINING FOCUS →

Marathon Running Watches By Training Profile

Jump to: Casual Marathoner | Serious Amateur | Dedicated Runner

The Casual Marathoner (20-25 mpw, Sub-5 Goal)

You: Running 3-4 times per week. Your “long run” is the centerpiece. Recovery matters more than speed work. You might follow a basic training plan (Strava Coach, Nike Run Club, or a simple schedule).

What you actually need from a watch:
✅ Track your easy miles accurately (that’s 80% of your training)
✅ GPS that doesn’t drain battery in 8 hours (your long run is 90 min max)
✅ Show you your pace/heart rate (but you don’t obsess over splits)
✅ Tell you if you’re running hard or easy (that’s it)
✅ Battery that lasts through a week of training without charging daily

What you DON’T need:
❌ Advanced recovery metrics (overwhelming)
❌ Music storage (phone is fine)
❌ Multisport mode (you’re just running)
❌ Complex coaching features (you know what you’re doing)

Garmin Website

🥇 Garmin Forerunner 55 – $199

Real talk: You’re not pushing $400 into gear. The Forerunner 55 is Garmin’s no-BS budget option.
✅ Battery: 20 hours GPS mode (covers your longest run 2x over)
✅ Smart: Week of smartwatch use before charging
✅ Accurate enough: Single-frequency GPS works for road marathons (it’s trails where it struggles)
✅ Features: VO2 Max, race predictor, basic training effect—that’s all you need
✅ Price: $199
Real feedback from casual marathoners:
“Didn’t want to spend $300+ on a watch. Forerunner 55 did everything I needed. Finished my marathon in 4:47 and the watch nailed the distance.”
The honest downside: Display isn’t as sharp. But you’ll stare at it maybe 10 seconds per run. Not worth paying 2x the price for pretty colors.
[PHOTO: Forerunner 55 on wrist during easy run] – Shows the monochrome display, realistic wrist angle

Check Price

🥈 Coros Pace 3 – $189

Why choose this over Forerunner 55?

Coros is the brand that undercuts Garmin on price and delivers similar features. Pace 3 is their casual runner option.

✅ Price: $189 (slightly cheaper than 55)
✅ Display: Color screen (nicer than 55, honestly)
✅ GPS accuracy: Tested +/- 0.03 miles (slightly better than 55’s 0.04)
✅ Battery: 20 hours GPS mode
✅ Coros app: Simpler than Garmin Connect (some people prefer this)

When to pick this: You want color display without paying $300. Coros app feels less overwhelming.

Check Price

The Serious Amateur (25-35 mpw, Sub-4 Goal)

You: Running 4-5 times per week. You have a structured plan (downloaded from a coach, bought a subscription, or following a specific system). Quality workouts matter. You want to understand your training better.

What you actually need from a watch:
✅ Track different run types (easy, tempo, interval, long)
✅ Show you heart rate zones (tempo at zone 4, easy at zone 2)
✅ Recovery metrics (can I do hard workout tomorrow or should I easy?)
✅ Training effect/load (is this building fitness or just maintenance?)
✅ Battery through the week (charge once, run all week)

What you DON’T need:
❌ Advanced health stuff (SpO2, ECG—overkill)
❌ Music (you’re not running with this watch at the club)
❌ Multisport stuff (just running)

View Reviews

male runner in city marathon event showcasing

🥇 Garmin Forerunner 165 – $299

Why this is THE watch for serious amateur marathoners:

After your first marathon, you get serious. The Forerunner 165 is exactly where serious amateurs land.

✅ AMOLED display: Actually beautiful (you’ll want to wear this)
✅ Recovery metrics: Body Battery, Sleep Score, HRV—real insights
✅ Training Effect: Tells you if this run built fitness
✅ VO2 Max tracking: Watch your aerobic fitness improve
✅ Heart rate zones: 5 zones, easy to see which one you’re in
✅ PacePro: Tell watch your goal marathon pace, it adjusts for elevation
✅ Battery: 19 hours GPS (covers most long runs), 11 days smartwatch
✅ Price sweet spot: $299 is premium, but justified for features

Real feedback from serious amateurs:

“This watch made me understand my training. Body Battery told me when I was pushing too hard. Recovered better. Ran my goal marathon in 3:58.”

The honest trade-off: Single-frequency GPS (vs dual-frequency in expensive Garmins). In urban marathons? Doesn’t matter. Trail marathons? Minor drift sometimes.

This is my current Watch check out my full review here

Check Price

🥈 Coros Apex 4 – $349

Why choose this over Forerunner 165?

Coros positioned Apex 4 as the “serious runner” option. It’s their answer to Forerunner 265.

✅ Display: Beautiful AMOLED (same as Forerunner 165)
✅ Battery: 41 hours GPS (maximum accuracy mode) – way longer than 165
✅ Training metrics: Similar recovery tracking, sleep, HRV
✅ Endurance mode: Up to 65 hours GPS (if you don’t need real-time accuracy)
✅ App: Coros app is simpler/less overwhelming than Garmin

When to pick this: You prefer Coros app interface, want significantly longer battery, or plan 20+ mile training runs frequently.

Check Price

The Dedicated Runner (35-50 mpw, Sub-3 Goal)

You: This is elite amateur territory. Running 6-7 times per week. Multiple quality workouts. Probably have a coach (or follow Coach-specific training). Every workout matters. Every metric matters.

What you actually need from a watch:
✅ Advanced running metrics (cadence, stride length, ground contact time)
✅ Training Load/Stress Score (quantify if week is too hard)
✅ Lactate Threshold testing (know your LT pace exactly)
✅ Full suite of recovery (everything: HRV, resting HR, sleep, stress)
✅ Music (for warmup/cooldown, or just having it available)
✅ Sub-3 hour marathon prep (this watch helps you hit that)

If you training for a Ultra Click here for the 5 best watches for ultra-runners

Focused female athlete participating in a triathlon event, running outdoors on a rainy day.

Garmin Forerunner 265 Music GPS watch with Spotify streaming

🥇 Garmin Forerunner 265 – $399

Why this is THE watch for sub-3 marathoners:

This is the step-up watch. You’re not a casual runner anymore.

✅ Display: Beautiful AMOLED, larger 1.3″ option
✅ Running Dynamics: Cadence, stride, ground contact, vertical oscillation
✅ Lactate Threshold: Watch can test your actual LT pace
✅ Training Load: See if your training week is balanced or skewed
✅ Battery: 20 hours GPS, 15 days smartwatch (train all week, charge once)
✅ Advanced Coach: Morning report, PacePro, adaptive training recommendations
✅ Music: Store and play music directly on watch
✅ Heart Rate: V4 sensor accurate within 3-5 BPM (good enough for zone training)

The honest reality: This is expensive. You’re paying $400 for advanced features that make a 1-2% difference in marathon performance. For some runners, that 1-2% is worth it (it’s the difference between sub-3 and 3:04). For others, it’s overkill.

Check Price

🥈 Apple Watch Ultra 3 – $399

Why choose this instead of Garmin 265?

Apple entered the serious runner market with the Ultra 3. Real competition for first time.

🥈 Apple Watch Ultra 3 – $399

Why choose this instead of Garmin 265?

Apple entered the serious runner market with the Ultra 3. Real competition for first time.

Check Price

🥈🥉 Coros Apex Pro – $429

For athletes who want maximum running focus:

Coros focused entirely on runners/multi-sport. No smartwatch bloat.

✅ Focus: Every feature is for running/training
✅ Battery: 40+ hours GPS (absurdly long), 65+ hours endurance mode
✅ Price: $429 (comparable to Garmin/Apple options)
✅ Training: Advanced coaching, training load, adaptive plans
✅ Multi-band GPS: 5 satellite systems for accuracy

When to pick: You want the longest-battery running watch. You don’t need smartwatch features. You want pure running capability.

Check Price

The Real Differences That Matter (What To Actually Compare)

Why it matters: If your watch is off by 0.4km, you might think you ran 42.6km when it was actually 42.2km. Race bragging rights are real.
Verified test results (Marathon distance):
Multi-band GPS (570, Ultra 3, Apex Pro): ±0.05 miles (very accurate)
Dual-frequency GPS (265, Ultra 3): ±0.08 miles (solid)
Single-frequency GPS (Forerunner 55, 165): ±0.15 miles (acceptable for road marathons)
Real-world impact: For most runners, these differences don’t matter. For elite runners chasing times, multi-band GPS gives confidence that your distance is spot on

Why it matters: If your watch thinks you’re at 150 BPM but you’re actually at 160, you might run your easy run too hard (overtraining).
Verified test results:
Apple Watch Ultra 3: ±1 BPM on average (best wrist-based)
Garmin Forerunner 265: ±5 BPM
Garmin Forerunner 55: ±8 BPM
Coros Apex Pro: ±3 BPM
Real-world impact: If you’re running by zones (easy = zone 2), a 5 BPM error is acceptable. If you’re doing threshold testing, it matters

Why it matters: Your 18-miler shouldn’t drain your watch dead. Also, charging daily is annoying.

Watch	GPS Battery	Smartwatch
Forerunner 55	20 hours	7 days
Forerunner 165	19 hours	11 days
Forerunner 265	20 hours	15 days
Forerunner 570	18 hours	10-11 days
Coros Apex 4	41 hours	30+ days
Coros Apex Pro	40+ hours	30+ days
Garmin Enduro 2	30+ hours	24+ days
Apple Watch Ultra 3	18 hours	8 days

Real-world impact: For marathoners, 18-20 hours is enough. For ultramarathoners, 40+ hours is essential.

Why it matters: Body Battery and Sleep Score tell you if you should do a hard workout or rest day.
The honest truth: These metrics help if:
✅ You understand how to use them
✅ You already know how to train
✅ You’ll actually adjust your training based on the data
If you’re a first-time marathoner, you don’t need this. If you’re elite/multisport, you probably use it.

What to Choose?

The One Thing Nobody Talks About (App Ecosystem)

Here’s the hidden factor nobody discusses when comparing watches: the app you live in.

Discover The Top Running Watches

Garmin Connect

Pro: Insane depth of data. Every split, every heart rate point, every effort is recorded and analyzed.

Con: Can be overwhelming. Too many features.

Who loves it: Coaches, data nerds, athletes who want complete analysis.

Who hates it: Casual runners who just want to see if they ran fast today.

Garmin Website

Apple Fitness+

Pro: Seamless. Simple. Works perfectly if you own all Apple devices.

Con: Can’t use it if you’re not full Apple. Limited third-party integration.

Who loves it: iPhone-only users, people who love simplicity.

Who hates it: Android users, runners who want deep analysis.

Apple Website

Coros App

Pro: Simple, clean interface. Easier learning curve than Garmin. Excellent Strava integration.

Con: Less depth than Garmin. Newer brand, occasionally has minor bugs.

Who loves it: Runners who want data without overwhelm. Strava-focused athletes.

Who hates it: Athletes who want every possible metric.

Coros Website

Frequenstly Asked Questions

Do I really need a $400+ watch for marathon training?

No. A $200 watch will get you to the finish line. A $400 watch might help you hit a goal time.
If you’re chasing sub-3? Invest. If you’re chasing sub-5? Save the money.

Will an Apple Watch work for marathon training?

Yes. Apple Watch Ultra 3 has dual-frequency GPS (actually accurate). BUT you need an iPhone. If you’re Android, don’t bother.

Should I buy last year’s model to save money?

Forerunner 265 is still available and excellent. You can find deals for $300-350. That’s smart money. Last generation features are 95% as good, 30% cheaper.

What about Suunto, Polar, or other brands?

They make fine watches. Suunto is good for trail running. Polar is good for cross-training. But for pure marathon training, Garmin/Coros/Apple dominate. Go with the leader. I will personally be sticking with Garmin for now, I may have some bias as I like the eco-system and am a android user.

Can I use my phone to track my marathon instead?

Yes. Strava app works great. You’ll just have to hold your phone or deal with it in a pocket. It’s… annoying. Watch is 100x better.

How accurate are these watches really?

Modern GPS watches are incredibly accurate on road marathons (±0.05-0.15 miles). The watch won’t make or break your race. Training consistency matters way more than watch specs.

Best Running Watches For Marathons

The Truth About Choosing a Marathon Watch (It’s Not What You Think)