Privacy Policy
CoastFinder is an app for looking at the water. It does not need to know who you are, and it is built so that it cannot find out.
Last updated 29 September 2026
CoastFinder collects no personal information. There is no account, no analytics, no advertising and no third-party tracking of any kind.
What the app uses your phone for
To draw a label on the right part of the sea, CoastFinder needs three things from the phone. All three are used on the device, in the moment, and none of them are recorded or transmitted.
| Sensor | Why it is needed | Where it goes |
|---|---|---|
| Location | To work out which charted features are in front of you, how far away they are, and where the horizon falls for your eye height. | Stays on the device. |
| Compass and motion | To know which way the phone is pointing and how it is tilted, so the labels stay on the features as you turn. | Stays on the device. |
| Camera | To show the live view of the water that the labels are drawn over. | Displayed only. No photo or video is saved, and no image is analysed, uploaded or sent anywhere. |
Nothing in the picture is recognised. The app knows where you are, which way you are looking, and where every charted feature sits; the rest is arithmetic. You can decline camera or location access and still use the map, search and the manual location mode.
What leaves your phone, and when
CoastFinder is designed to work with the radio off. Something can leave your phone in four situations, and it is worth being precise about each one.
Checking for and downloading regions
Two regions are built into the app. When it is online, the app fetches the list of other regions from coastfinder.app when it starts and when you open Regions, and when you download one it requests that region's file from the same place. These are ordinary web requests for public files. The website's host sees the IP address that asked and which file was requested, as any web server does. No position, account or identifier is sent. Downloaded regions then work with no connection at all.
Checking for app updates
Small fixes to the app's own code can arrive between App Store releases through Expo's update service, which the app is built with. When it is online, the app asks that service whether a newer version exists. The request carries the app version, the platform, and a random installation number the update service creates the first time the app runs, which Expo uses to roll updates out in stages and to count how many phones have received one. It is not linked to your name, your Apple ID or your advertising identifier, and it carries no position. Deleting the app deletes it. Expo's handling of the request is governed by Expo's privacy policy.
Refreshing tide predictions
Depth estimates are corrected for the tide. Every region pack ships with about sixty days of tide predictions built in, so this works offline. When the app is online and those predictions are running out, it refreshes them from NOAA's public Tides and Currents service. That request contains a tide station identifier and a date range. It does not contain your position, but the station is one near you, so it does indicate the general stretch of coast you are on. NOAA receives the request and your IP address, and their handling of it is governed by their own privacy policy. No key or account is involved.
Reporting a problem
Every feature's detail card has a link to report a problem with it: a wrong position, name, depth or height, or a feature that is not there. Choosing one opens a draft email, addressed to support@coastfinder.app, in your own Mail app or the share sheet. The draft contains the feature's name, position and source, the region pack and app version, your GPS position and its accuracy, your eye height, the bearing and distance the app computed, and, if you took a sighting, the heading and tilt of the phone when you did. It is all written out in plain text. The app sends nothing. The email leaves your phone only if you press Send, from your own email account, and you can read every line before you do. Whatever you send is used only to check and correct the chart data, and is not linked to anything else, because there is nothing to link it to.
Saved views and pins
Saved views and custom pins are stored only on your phone, in the app's own storage. Nothing you save is uploaded or sent anywhere, so we never hold a copy. They are listed in the app, under More; deleting one there removes it, and deleting the app removes all of them. A position of yours leaves the phone only when you send a problem report yourself, and never otherwise.
What we do not do
- No analytics or crash-reporting SDK is embedded in the app.
- No advertising, no advertising identifier, and no ad networks.
- No tracking across apps or websites, and no data is shared with data brokers.
- Nothing is sold. There is no circumstance in which we would have anything to sell.
- No email address is requested, because there is no account to create.
Children
CoastFinder is rated 4+ and is suitable for all ages. It does not knowingly collect personal information from anyone, of any age, so it collects none from children either.
Changes
If this policy changes, the date at the top changes with it. If a change ever means the app starts collecting something it does not collect today, that will be said plainly here and in the App Store release notes, not buried in a revision.
Contact
Questions about privacy: