2026 comparison
Garmin vs COROS for marathon training.
Both brands make watches that nail Sub-3, Sub-3:30, and Sub-4 training. The decision is rarely about brand quality — it is about wrist comfort, battery, ecosystem, and budget. Below is a side-by-side breakdown, plus the free app that lets you use both at once.
Side-by-side
| Garmin | COROS | |
|---|---|---|
| Model range | Wide (Forerunner / Fenix / Epix / Venu / Instinct) | Focused (Pace / Apex / Vertix) |
| Entry running watch | Forerunner 165 (~USD 250) | Pace 3 (~USD 230) |
| Battery (GPS run) | ~19-31h Forerunner; up to 89h Fenix 8 | ~38h Pace 3; up to 140h Vertix 2 |
| Battery (smartwatch) | 2-14 days | ~24 days Pace 3; up to 60 days Vertix 2 |
| AMOLED display | Forerunner 165/265, Epix, Venu | None (transflective MIP) |
| Dual-frequency GPS | Forerunner 265/965, Fenix 7 Pro+, Epix Pro | Apex 2 Pro, Vertix 2 |
| Wrist heart rate accuracy | Generally strong | Improving (Pace 3 weakest) |
| Running dynamics | Most mid+ models | Apex 2 Pro / Vertix 2 only |
| Training-readiness AI | Strong (Body Battery, Recovery) | Basic (EvoLab) |
| Third-party app ecosystem | broad | limited |
| Companion app | Garmin Connect | COROS app + Training Hub |
| Goal-driven marathon training | Limited (Coach feature exists) | None native |
| SUB integration | ✓ Auto-sync, auto-complete workouts | ✓ Auto-sync, full running dynamics |
Recommended pairings by goal
- First marathon / Sub-5 / Sub-4:30: Forerunner 165 or COROS Pace 3. Pace 3 is the value pick.
- Sub-4 / Sub-3:30: Forerunner 265 or COROS Pace 3. Forerunner 265 for AMOLED + training-readiness; Pace 3 for battery + price.
- Sub-3 / Sub-2:45 (road): Forerunner 965 or COROS Apex 2 Pro. Apex 2 Pro for running dynamics; Forerunner 965 for software depth.
- Trail / Ultra: Garmin Fenix 7 Pro / Epix Pro or COROS Vertix 2. Vertix 2 dual-frequency GPS is the practical winner for technical terrain.
Use both with SUB
The most honest answer to “Garmin or COROS” is often: both. People keep a Forerunner for road training and a Pace 3 for ultras, or wear both to compare GPS tracks. SUB makes that work without double-counting.
- Connect both Garmin Connect and your COROS account to the same SUB account.
- Monthly and weekly mileage take the maximum across sources — never the sum. Totals stay honest when you wear both on the same run.
- Coach-assigned workouts auto-complete from whichever watch syncs first.
- Pick a marathon goal once; SUB calculates target pace and surfaces matching races.
Frequently asked questions
Garmin vs COROS — which is better for marathon training?
Both work. Garmin has the wider model range (Forerunner 165 / 265 / 965, Fenix, Epix) and stronger heart rate accuracy on the wrist. COROS Pace 3 is lighter, has longer smartwatch-mode battery life, and costs roughly half a Forerunner 265. Apex 2 Pro and Vertix 2 add full running dynamics. For pure marathon training there is no decisive winner — your budget, wrist comfort, and battery preference matter more than brand.
Garmin Forerunner 265 vs COROS Pace 3 — which for sub-3?
Both nail sub-3 training. Forerunner 265 has a brighter AMOLED screen and stronger training-readiness metrics; Pace 3 is lighter, has roughly twice the smartwatch-mode battery life, and costs roughly half. Forerunner 265 wins on software depth and recovery suggestions; Pace 3 wins on price-per-feature. Either is excellent for sub-3.
Garmin Fenix 7 vs COROS Vertix 2 — which for adventure marathons?
Fenix 7 is more refined: better software polish, sapphire glass option, better wrist HR. Vertix 2 has dual-frequency GPS (more accurate in canyons / tall buildings), 60-day standby battery, and dual-band heart rate. For trail / ultra: Vertix 2 dual-frequency GPS is the practical winner. For road marathons: Fenix 7 is the safer pick.
Garmin Epix Pro vs COROS Apex 2 Pro — which for marathon training?
Epix Pro: AMOLED, broader software, ~50% more expensive. Apex 2 Pro: dual-frequency GPS, longer battery, full running dynamics (stride length, vertical oscillation, ground contact time), titanium bezel. For pure training: Apex 2 Pro is the value pick. For all-around: Epix Pro wins on software polish.
Can I use Garmin and COROS together for training?
Yes. With SUB, connect both Garmin Connect and your COROS account to the same SUB account. SUB intelligently deduplicates: monthly and weekly mileage take the maximum across sources (never the sum), so totals stay honest when you wear both watches on the same run. Coach-assigned workouts auto-complete from whichever watch syncs first. Free.
Is there an app that supports both Garmin and COROS?
SUB. SUB is the marathon training app that unifies Garmin Connect, COROS, Apple Watch (via HealthKit), and Polar in one account. Pick a marathon goal (Sub-3, Sub-3:30, Sub-4) and SUB calculates target pace; runs from any watch auto-sync; coach workouts auto-complete on sync. Free on iOS and Android.
Garmin Connect vs COROS Training Hub — which is better?
Both are logging and analytics tools. Garmin Connect has the deeper history, broader social features, and richer training-readiness suggestions. COROS Training Hub is cleaner and surfaces running dynamics more directly. Neither is goal-driven training; SUB adds that layer on top of either or both.