Submarius vs Navionics.
These apps aren't really competitors — they solve different problems. Navionics (now owned by Garmin) is a nautical charts platform: depth contours, navigation aids, tide-current vectors, and offline coastal maps. Submarius is a conditions forecasting app: "is today worth going?" with a bite score, water clarity forecast, and explainable factors. Most serious boaters end up using both.
| Feature | Submarius | Navionics |
|---|---|---|
| Detailed nautical charts (NOAA ENC + proprietary) | NOAA ENC | ✓ best in class |
| Depth contours | ✓ GEBCO | ✓ SonarChart™ |
| Offline chart download | ✓ (Pro) | ✓ |
| Turn-by-turn marine routing | — | ✓ (Plus) |
| Dock-to-dock navigation | — | ✓ |
| Tide & current predictions | ✓ with scoring | ✓ raw data |
| Single-number verdict (0–10) | ✓ | — |
| Bite score | ✓ | — |
| Water clarity forecast | ✓ | — |
| 10-day marine forecast | ✓ | Basic overlay |
| Shark tag alerts | ✓ free | — |
| Community spots | ✓ | Community edits (charts) |
| Works on web (no install) | ✓ | Mobile only |
| Annual price | $99 (Pro) | $22–$60 (regional) |
Who should use Navionics?
If your boat doesn't have a dedicated chartplotter, or if you want a backup for the one you have, Navionics is the gold standard on mobile. The SonarChart™ depth contours are genuinely crowdsourced and updated frequently. Dock-to-dock routing accounts for chart depths and low-clearance bridges. Offline charts for a trip to the Bahamas or the Keys are just worth it.
Captains, cruisers, and anyone navigating unfamiliar water — this is your tool.
Who should use Submarius?
Submarius answers a different question: should I take the boat out today? Not how do I get from here to there safely? (That's Navionics' domain.) If your decision each weekend is "is the bite on?" or "is viz good enough to dive?" or "should I wait until Sunday morning?" — that's where Submarius shines.
Specifically:
- Spearos and divers need the water-clarity forecast Navionics doesn't provide.
- Anglers get a bite score instead of having to mentally combine tide, moon, pressure, and wind themselves.
- Weekend warriors get a 10-day outlook that helps plan the right day, not just the current one.
- Anyone gets shark tag alerts, SOS, and buddy GPS — permanently free.
The complementary setup.
In practice many of our users run both. Check Submarius the night before ("verdict is GOOD, best window 6–9 AM, bite score 8.1"). Open Navionics when you're actually underway ("which channel, what depth, any chart hazards"). They're complementary tools, not either/or.
Looking for a Navionics alternative for charts?
Submarius isn't primarily a chart replacement — we use NOAA ENC (free, public-domain US nautical charts) as our base. That's excellent for coastal US waters, not matched to Navionics' SonarChart detail. If you specifically need that level of chart fidelity, use Navionics. We complement it; we don't replace it.