Built for the people who plan around the tide.
Tens of millions of Americans plan their day around the tide. The tools were either free but online-only and dated, or expensive social networks. Slackwater is the third option: a fast, private utility that shows the tide curve and times for your spots and the solunar bite, and it works with no signal.
Who it is for
The angler
Plans trips around the tide and the solunar bite, and fishes several spots.
The surfer
Times a session around the tide the break likes.
The boater
Wants tide and slack water for a safe, comfortable outing, and offline matters most on the water.
The beachgoer
Wants low-tide timing for the family beach day, clamming, or a paddle.
Private by design
Your spots, settings, and any logs live on your device and sync only through your own iCloud. There is no developer server storing your data, no account, no ads, and no tracking. Subscription state is the only thing that leaves the device, handled by the App Store.
About the data
Tide predictions are computed on device from NOAA CO-OPS harmonic constituents, US-government public data, using standard harmonic synthesis. Solunar windows come from sun and moon position.
Tide predictions are estimates for reference only. They are not for navigation or life-safety decisions. Always consult official NOAA tide tables and nautical charts.