Terms of use
Effective 3 October 2026 · applies to the Swell Signal app and to swell-signal.com
Read this one
Swell Signal is a forecast. It is not a navigation aid, not a safety system and not a substitute for looking at the water. Ship wakes are made by working vessels carrying people and cargo, in shipping lanes, in cold water, on a schedule that is not yours.
A prediction can be early, late, wrong, or absent for a wave that arrives anyway. The vessel-traffic and weather feeds it reads can be delayed or offline without warning. You are responsible for your own safety, for keeping clear of vessels and their traffic lanes, and for obeying every applicable navigation rule and local regulation. If the two disagree, the water wins.
LINEUP. LINEUP shows other vessels' broadcast positions, which can be minutes old, moved forward by our estimate, with the wake our model expects. It draws a keep-out zone around every vessel as a reminder, not a boundary: the Navigation Rules, local safety zones and the vessel's own wake and wash decide where you may be. Vessels without AIS never appear. You are responsible for keeping at least 300 feet from every vessel, for never crossing ahead of one, and for the people you tow.
Using the service
Use it for your own riding and forecasting. Do not use it to interfere with, approach or obstruct a vessel. Do not scrape it, resell its output, or hammer the API in a way that degrades it for other people. Do not attempt to reach another person's account, pins or screens.
Access may be rate-limited or withdrawn if a use is harming the service or another user.
Accounts
An account is optional and free. You are responsible for keeping your password to yourself. Content you submit — a handle, a wave report, a comment — is yours; by posting it you allow it to be displayed in the app and used, in aggregate, to calibrate the wave physics. Anything abusive, or aimed at another person, may be removed.
You can delete your account at any time from Settings → Account. That removes the account and the content attached to it.
Price
The core app is free: the map, pins with their live pass times, tides, wind and ferries. Push alerts for your pins are part of Swell Signal Pro, an optional paid tier — see Subscriptions below. If a paid tier beyond Pro is introduced later, the features you already rely on will not be taken away without notice.
Subscriptions
Swell Signal Pro (ship-pass push alerts, currently the Alerts, Supporter and Patron tiers) is sold only through the iOS app, as an auto-renewing monthly subscription billed by Apple. The price is shown before you buy. A subscription renews automatically at the end of each period unless you cancel at least 24 hours before it renews.
Manage or cancel a subscription any time in Settings → [your name] → Subscriptions on the device that bought it — we cannot cancel it for you. Refunds are handled by Apple at reportaproblem.apple.com, not by us. Deleting your Swell Signal account does not cancel an active Apple subscription; cancel that separately in Apple ID settings.
Pro's features may change over time. Ship alerts depend on live vessel-traffic data that can be delayed, incomplete or unavailable, exactly like the free forecast above — a Pro subscription is not a promise that an alert will arrive, or arrive on time. To the fullest extent the law allows, Swell Signal is not liable for a missed, late or wrong alert. Never rely on an alert for navigation or safety, and never rely on its absence to mean nothing is coming.
Data sources
Tides and currents come from NOAA, ferry sailings from WSDOT, and vessel positions from a commercial AIS feed. Those are their data, published under their own terms, and their accuracy and availability are not something Swell Signal controls. NOAA tide predictions are predictions: actual water level varies with weather.
Around the rest of the coast: ferry schedules from San Francisco Bay Ferry (WETA), the San Diego Metropolitan Transit System (MTS) and TransLink, published as GTFS feeds. Shipping lanes and channels drawn on the chart come from the U.S. Army Corps of Engineers National Channel Framework and NOAA ENC Direct, with thanks. The shoreline, ferry routes and some lanes are © OpenStreetMap contributors, available under the Open Database License (ODbL).
Some of the data used in this product or service is provided by permission of TransLink. TransLink assumes no responsibility for the accuracy or currency of the Data used in this product or service.
Availability
The service is provided as it is, with no promise of uptime, accuracy or fitness for any particular purpose, to the fullest extent the law allows. It runs on modest hardware and it can go down. To the extent permitted by law, Swell Signal is not liable for any injury, loss or damage arising from use of the service or from reliance on a forecast.
Nothing here limits a liability that cannot lawfully be limited.
Changes
These terms can change; the effective date at the top moves when they do. Continuing to use the service after a change means accepting it.
Governing law
These terms are governed by the laws of the State of Washington, USA.