⚓ Supplemental Coastal Reference Tool

Know Your Nearest
Coastline. Anywhere.

A GPS-based reference tool that shows real-time distance and bearing to the nearest coastlines. Zoom levels z7–z9 are free forever — unlock higher detail (z10–z12) or ship density as one-time purchases. Not a replacement for official nautical charts or certified navigation equipment.

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Download on the App Store

190+

Countries Covered

100%

Works Offline

Free

z7 – z9 Maps

From $2.99

Optional Add-ons

⚠️ Important Safety Notice CoastNav is a supplemental GPS-based reference tool intended to assist situational awareness. It is NOT a certified marine navigation system and must NOT be used as your sole or primary means of navigation. Coastline data is sourced from OpenStreetMap and may contain errors, omissions, or outdated information. It does not include tidal data, water depths, underwater hazards, or information certified by any hydrographic authority.

Always carry official nautical charts, maintain proper watch, comply with maritime regulations (COLREGS), and ensure all required safety equipment is on board. The developer assumes no responsibility for navigation decisions made using this app.

✦ Features

Your coastline reference.
Always offline.

CoastNav is a GPS-based reference tool that works offline — designed to supplement your primary navigation aids, not replace them. Zoom levels z7–z9 are free forever; upgrade to z10–z12 or ship density as one-time purchases when you need more detail.

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Global Offline Maps

High-detail coastline and land polygon maps for the entire world, stored on your device. No cell signal needed — ever.

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Nearest Coastline Finder

Tap anywhere on the map to instantly see bearing and distance to the nearest coastline point — in nautical miles or kilometers.

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Multi-Point Distance Tool

Survey multiple coast distances from any position simultaneously. All bearings and distances displayed in a clean, organized panel.

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GPS Positioning

Center the map on your current location instantly. Coordinates displayed in degrees, minutes, and seconds format.

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Built-in Compass

Live compass overlay keeps you oriented at a glance — heading updates in real time so you always know which way you're facing on the water.

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Multiple Zoom Levels

Choose from detail levels z7 to z12 — from ocean-scale overview to high-resolution coastal detail. Download only what you need.

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Dark & Light Themes

Optimized dark theme for night watches, light theme for bright conditions, and auto-sync with your device system preference.

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Battery Optimized

One-shot GPS requests, not continuous tracking. Tile rendering is hardware-accelerated. Designed for long passages with no charger.

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Nautical Miles & km

Toggle between nautical miles (NM) and kilometers for all distance measurements. The app remembers your preference.

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Ship Density Overlay

Optional add-on: visualize global maritime traffic density as a heatmap overlay on your coastline map. Separate one-time purchase.

⚙️ How It Works

Ready to navigate in minutes.

No account. No sign-in. No subscription. Use alongside your official charts and navigation equipment.

Install the App

Download CoastNav free from the App Store. No registration required. Zoom levels z7–z9 are included at no cost.

Download Map Data

Choose your detail level and download coastline tiles over Wi-Fi. One-time download — works forever offline. Upgrade to z10–z12 anytime.

Navigate at Sea

Open the map, tap the locate button to center on your GPS position, then hold anywhere to measure coast distances.

Read the Results

See bearing and distance to the nearest coastline points, displayed on-map with a clean detail panel.

Nearest Coast

Always know how far you are from shore.

Whether you're planning a passage, caught in changing weather, or simply want situational awareness — CoastNav instantly calculates bearing and distance to the nearest coastline from any point on the map.

Survey up to 15 nearest coast points simultaneously
True bearing with compass direction label (N, SSE, NNW…)
Distances in nautical miles or kilometers
Visual dashed bearing lines on the map
Toggle individual lines on/off in the detail panel

Distance Measurements

Full measurement panel. Clean & organized.

Hold on any ocean position to activate surveying. CoastNav draws bearing lines to the nearest coastline points and presents them in an organized measurement sheet — complete with distance and bearing for each line.

Numbered measurement lines with color coding
Show/hide individual lines with a tap
All measurements update live as you pan the map
North-up compass rose always visible

🌊 Map Data

OpenStreetMap-powered.
Global. Open. Offline-ready.

Coastline data is sourced from the OpenStreetMap global dataset — the same trusted open-data foundation used by many professional mapping services worldwide.

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Global Coverage
Every coastline on Earth

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August 2025 Dataset
Recently updated coastlines

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Open Data License
ODbL — transparent sourcing

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MBTiles Format
Compact, fast, offline-ready

⚠️ Data Accuracy Notice: Coastline data is sourced from OpenStreetMap (crowdsourced) and is provided for general reference only. It may contain errors or omissions and is not certified by any hydrographic authority (IHO, UKHO, NOAA, etc.). Higher zoom levels (z10–z12) show greater detail but do not increase the accuracy or certification level of the underlying data. Always verify against official nautical charts before making any navigation decision.

💎 Pricing

Free to start. Pay only for the detail you need.

No subscriptions. No trial period. Zoom levels z7–z9 are free forever. Unlock higher detail or ship density as one-time purchases.

Free

^$0

Free forever — no time limit

✅ Coastline maps z7, z8, z9
✅ Nearest coastline navigator
✅ Multi-point distance tool
✅ GPS positioning
✅ Built-in compass
✅ Dark & light themes

Detail — z10

^$4.99 once

Harbour & river approach detail

✅ Everything in Free
✅ Zoom level 10 maps
✅ Fine coastal detail
✅ Lifetime unlock

⭐ Popular

Detail — z11

^$5.99 once

High-resolution coastal detail

✅ Everything in Free
✅ Zoom level 11 maps
✅ Very fine coastal detail
✅ Lifetime unlock

Detail — z12

^$6.99 once

Maximum resolution available

✅ Everything in Free
✅ Zoom level 12 maps
✅ Maximum coastal resolution
✅ Lifetime unlock

Ship Density

^$2.99 once

Maritime traffic overlay

✅ Ship density heatmap
✅ Global maritime traffic data
✅ Separate one-time purchase
✅ Works with any map level

Prices may vary by region. All payments processed securely by Apple App Store. iOS only. Refund policy applies.

🔒 Privacy

Your data stays on your device.
Always.

CoastNav is built with a privacy-first philosophy. We don't create accounts, don't track you, and don't share anything with third parties.

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No Account Required

Zero sign-up, zero email, zero password. Just install and use.

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No Tracking

No analytics SDK, no advertising ID, no behavioral tracking whatsoever.

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Location — Only When You Ask

GPS accessed only when you tap the locate button. Never in background.

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No Cloud Sync

All data stays on your device. Nothing uploaded to our servers.

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No Third-Party SDKs

Built with Apple's native frameworks only. No hidden data pipelines.

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Apple Handles Payments

We never see your card details. All billing via Apple's secure system.

Read our full Privacy Policy and Terms of Service.

Know Your Nearest Coastline. Anywhere.

Your coastline reference.Always offline.