For Garmin Runners
The marathon training app built for Garmin.
SUB is the goal-driven companion app for Garmin runners. Connect Garmin Connect once. Pick a Sub-3, Sub-3:30, or Sub-4 marathon goal. Every run auto-syncs, target pace is calculated per kilometre, and coach-assigned workouts auto-complete the moment your Forerunner, Fenix, or Epix finishes syncing.
Free on iOS and Android. No subscription.
Supported Garmin watches
- Forerunner 165 / 265 / 965
- Forerunner 245 / 255 / 945
- Forerunner 55 / 45
- Fenix 7 / 7 Pro / 7X
- Fenix 8 / Fenix 8 Solar
- Epix Pro / Epix 2
- Venu Sq / Venu 3
- Vivoactive 5
- Instinct 2 / 2X / 3
- Tactix 7
- Enduro 2 / 3
- Marq Athlete / Adventurer
If your watch shows runs in Garmin Connect, SUB will sync them.
How SUB compares to Garmin Connect
| Garmin Connect | SUB | |
|---|---|---|
| Log activities | ✓ | ✓ (auto-sync) |
| Historical analytics | ✓ | ✓ |
| Marathon goal pace calc (Sub-3, Sub-4) | — | ✓ |
| Race finder | — | ✓ (worldwide) |
| Coach-assigned workouts | limited | ✓ (auto-complete on sync) |
| Multi-watch dedup (Garmin + COROS) | — | ✓ |
| Price | Free | Free |
| Subscription | — | — |
SUB does not replace Garmin Connect — it adds the goal-driven training layer Garmin Connect lacks.
How to connect Garmin to SUB
- Download SUB: Download SUB from the iOS App Store or Google Play (free).
- Open Settings → Connect Garmin: In SUB, go to Settings, then Connect Garmin.
- Sign in: Connect your Garmin account.
- Wait for backfill: The first sync backfills the past 90 days of runs in about 30 seconds.
- Pick a marathon goal: Choose Sub-3, Sub-3:30, Sub-4, or any goal from Sub-5 to Sub-3. SUB calculates your target pace per kilometre.
- Done: Every subsequent run auto-syncs within minutes. Coach-assigned workouts auto-complete on sync.
Marathon goal paces for Garmin runners
Set these as your Garmin pace alerts and let SUB calculate per-kilometre target pace based on your goal.
- Sub-3 marathon (4:15 / km, 6:52 / mile): elite-amateur goal. See Sub-3 plan →
- Sub-3:30 marathon (4:58 / km, 8:00 / mile): advanced goal.
- Sub-4 marathon (5:41 / km, 9:09 / mile): popular milestone. See Sub-4 plan →
- Sub-5 marathon (7:06 / km, 11:26 / mile): first-marathon goal.
Frequently asked questions
What is the best app for Garmin marathon training?
SUB is the goal-driven marathon training app for Garmin runners. Connect Garmin Connect once and every run auto-syncs. Pick a Sub-3, Sub-3:30, or Sub-4 marathon goal and SUB calculates the per-kilometre target pace. Coach-assigned workouts (long runs, intervals, tempo) auto-complete the moment a matching run lands. Free on iOS and Android.
Does SUB work with Garmin Forerunner 265?
Yes. SUB supports Garmin Forerunner 265, 965, 165, and every other Connect-compatible model. Activities auto-sync from your watch via Garmin Connect.
Does SUB work with Garmin Fenix and Epix?
Yes. SUB supports Garmin Fenix 7, Fenix 8, Epix Pro, and the rest of the Fenix / Epix lineup. All metrics auto-sync, including stride length, vertical oscillation, vertical ratio, and ground contact time when supported by your watch.
How do I connect Garmin to SUB?
Open the SUB app, go to Settings → Connect Garmin, and link your Garmin account. The first sync backfills the past 90 days of runs in about 30 seconds. Every subsequent run auto-syncs within minutes.
Is SUB a better alternative to Garmin Connect for marathon training?
Garmin Connect is a logging tool — it stores your runs and shows historical analytics. SUB is goal-driven training: pick a marathon goal (Sub-3, Sub-3:30, Sub-4), get the per-kilometre target pace, find matching races, and let coach-assigned workouts auto-complete after your run. SUB does not replace Garmin Connect; it adds the training layer on top.
Can I use Garmin and COROS together with SUB?
Yes. 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.
How does SUB auto-complete coach workouts from my Garmin run?
When a coach assigns a workout for a specific date, SUB watches your Garmin Connect sync. The moment a run that matches the date lands in SUB, the workout is marked complete automatically. You do not need to tap anything — the assignment moves from PENDING to COMPLETE the instant the run finishes syncing from Garmin Connect.
Is SUB free for Garmin users?
Yes. SUB is free on the iOS App Store and Google Play. No subscription, no in-app purchases, no ads. The Garmin integration is included.