# OpenSeaMap — The open nautical chart > Free, open-source worldwide nautical chart with navigation features and offline caching. (iPhone/iPad app by appdoctors UG.) - Source: https://appshunter.io/ios/app/openseamap/id495210783 (this page in markdown: same URL + `.md`) - Developer: [appdoctors UG](https://appshunter.io/developer/961029450) - Category: Navigation, Travel - Price: Free with in-app purchases (on sale, was $0.99) - Rating: 1.00/5 from 1 App Store ratings · 47 written reviews indexed - Age rating: 4+ - Requires: iOS 18.6 · 13 MB - Languages: American English, French (France), German (Germany) - Released: 2012-01-25 - Data updated: 2026-08-23 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/openseamap/id495210783/reviews.md ## What is OpenSeaMap? OpenSeaMap is a worldwide Opensource-project for creating a free nautical chart. Founded in 2009 the project gained a lot of attention lately adding more and more nautical information for free. Not even lights and other nautical infos are provided, but also more and more info layers like weather data, information about harbours and so on. As an add on to the OpenStreetMap this provides all missing info for nautical activities. OpenSeaMap is part of OpenStreetMap and uses the same database. FEATURES: - Free worldwide sea chart (incl. HD chart graphics) - Search for geolocations worldwide - Chartplotting with continuous tracking - Waypoints can easily be created, edited, deleted & exported - Mark locations in the chart - Zoom chart optically to fit your preferred reading size - Enter coordinates directly to be displayed in the chart - Offline caching of up to 1 million map tiles - Cleanup of chart cache data at any time To ensure future development and support of the OpenSeaMap app we encourage you to buy the In-App-Product "PRO". This will help keeping new updates and features coming. DISCLAIMER: OpenSeaMap is part of the OpenStreetMap and uses the same database. As an experienced navigator you should NEVER rely your descisions on one source of information alone. Please keep in mind that the OpenSeaMap can not replace official sea charts on bord of your boat. Please use the OpenSeaMap app only in conjunction with official sea charts and conforming to national and international regulations. Please recognize that no depth information is provided by this product. IMPORTANT: The continued use of the GPS can significantly decrease the battery level. ## Key features - Free worldwide sea chart - Chartplotting with tracking - Waypoint creation and export - Offline map caching - Mark and search locations - Adjustable chart zoom ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | OpenSeaMap Professional | $1.99 | one-time | ## Recent user reviews (10 of 47) All indexed reviews: https://appshunter.io/ios/app/openseamap/id495210783/reviews.md ### 1/5 — Entfernung messen geht nicht in der kostenlosen Version *2026-08-15* Entfernung messen geht nicht in der kostenlosen Version O ### 1/5 — Wichtige Funktionen fehlen *2026-08-15* Leider fehlen mir wichtige Funktionen wie aktuell Wassertiefe Distanz zu Wegpunkten das anpeilen von Wegpunkten und die Navigation zu entsprechenden Wegpunkten. Bei der fortlaufenden Ortung wird ständig der Bildausschnitt zurückgesetzt zum aktuellen Positionen das funktioniert auch nicht richtig. ### 1/5 — Schwach *2026-08-11* Wenig aussagekräftig ### 1/5 — Can’t create a route, App crashes *2025-11-21* First time user - I was looking forward to simply plotting a route over a marine chart, to visualize the likely vessel path before a recent South Korea marine accident. I’m usually quite adept at making apps work for me, including several other marine apps, but I couldn’t find a way to create a route on the map in this one. The bar at the bottom appears to be where an option like that might appear, but tapping on it just causes the app to immediately crash. I did try creating a few waypoints, but I couldn’t find a way to create a route that follows them. ### 1/5 — Ein Witz das Ganze *2025-11-17* Hat jemand eine Navi App im Auto, wo die Straßen nicht eingezeichnet sind? Das wichtigste an einer Seekarte sind die tiefen Linien und die Untiefen. Das ist ein Witz das Wichtigste vom ganzen fehlt. Setzen fünf. 😂 ### 1/5 — useless App *2025-10-23* no function to import downloaded chats, thus not for offline use. insufficient info content for navigation. ### 3/5 — Guter Ansatz… *2025-10-09* …aber ich frage mich, ob ich die Entfernung zwischen zwei Punkten messen kann. Sie wird auch zwischen Wegpunkten nicht angezeigt. Das schränkt die Brauchbarkeit für die Planung schon sehr ein. Leider finde ich auch keine Dokumentation zur Funktionalität. ### 3/5 — Totally ???? *2024-12-22* Unless you have microscopic eye; u don’t buy PRO u will sail blind ### 1/5 — wheres the chart data? *2022-12-16* had high hopes for open crowd sourced charting, this isnt it. for marine navigation, even google streetmaps on sat view has more detail. willing to be told im wrong, but i deleted it after 15 minutes. ### 1/5 — Open sea map *2022-12-12* iOS 16.1.2. It’s not usable. Crashes when I do anything. ## Frequently asked questions about OpenSeaMap ### What is OpenSeaMap? OpenSeaMap is a free, open-source project that creates a worldwide nautical chart. It provides detailed nautical information, weather data, and harbor details, functioning as an add-on to OpenStreetMap. ### Does OpenSeaMap offer offline navigation? Yes, OpenSeaMap allows for offline caching of up to 1 million map tiles. This feature enables navigation even without an internet connection. ### How much does OpenSeaMap cost? The OpenSeaMap app is free to download and use. However, it offers an optional in-app purchase called "PRO" to support future development and new features. ### What devices is OpenSeaMap available on? OpenSeaMap is available for iPhone and iPad devices, as indicated by its supported devices list. ### Is OpenSeaMap suitable for professional navigation? OpenSeaMap is a valuable tool but should not be relied upon as the sole source of information for navigation. It cannot replace official sea charts and should be used in conjunction with them and according to regulations. ### Does OpenSeaMap provide depth information? No, the OpenSeaMap product does not provide depth information. Users should be aware of this limitation when using the app for navigation. ### How often is OpenSeaMap updated? The app was last updated on July 8, 2025, with version 4.2. This indicates a recent update, suggesting ongoing development and support. ### What is the age rating for OpenSeaMap? OpenSeaMap has an age rating of 4+, making it suitable for a wide range of users, including younger individuals interested in nautical activities. ## Version history (last 5 releases) ### 4.4 — 2026-04-27 - NEW: Fixed issue on launch of the app - NEW: Updated the user interface to use the latest OS ### 4.2 — 2025-07-08 - NEW: Show all your waypoints in the map - NEW: Add new waypoints more easily - NEW: Modernised the whole app to run in multi-window environments (on iPad) - NEW: Modernised all icons used ### 4.1 — 2025-06-26 - Overall update, bugfixes and improvements ### 4.0 — 2025-06-26 - Overall update, bugfixes and improvements ### 3.4 — 2017-05-17 This app has been updated by Apple to display the Apple Watch app icon. - Improved information for customers ## Apps similar to OpenSeaMap | App | Rating | Price | Category | | --- | --- | --- | --- | | [NavShip - US Waterways](https://appshunter.io/ios/app/navship-us-waterways/id1249883240) | 4.5 (11) | Free | Navigation | | [Boatpark](https://appshunter.io/ios/app/boatpark/id1466777753) | — | Free | Navigation | | [Anchor Alarm / Watch](https://appshunter.io/ios/app/anchor-alarm-watch/id1428485893) | 4.7 (801) | Free | Navigation | | [Open Sea OpenSeaMap Browser](https://appshunter.io/ios/app/open-sea-openseamap-browser/id1028248846) | 3.2 (5) | Free | Navigation | | [NV Charts GPS Navigation AIS](https://appshunter.io/ios/app/nv-charts-gps-navigation-ais/id659569095) | 4.5 (114) | Free | Navigation | | [KartenWerft NavGo 2.0](https://appshunter.io/ios/app/kartenwerft-navgo-20/id1497036703) | 5.0 (1) | Free | Navigation | ## More apps by appdoctors UG - [Landlubber](https://appshunter.io/ios/app/landlubber/id366307784) - [Sea Weather Professional](https://appshunter.io/ios/app/sea-weather-professional/id384086202) - [Terminal RSS](https://appshunter.io/ios/app/terminal-rss/id435065283) - [Hackerspace Bremen](https://appshunter.io/ios/app/hackerspace-bremen/id707128929) - [Tasks Pro](https://appshunter.io/ios/app/tasks-pro/id1019859914) All apps by appdoctors UG: https://appshunter.io/developer/961029450 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-23.*