San Francisco Bay · planmyswim.com
Plan my Swim in the Bay
Disclaimer: Estimates only — always check conditions and swim at your own risk. This tool provides estimated data for informational purposes only. Always check current conditions, follow safety guidelines, and swim at your own risk. Water conditions can change rapidly and may differ from predictions.
Plan your splash 🌊
Three quick choices — your chart updates as you go.
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When do you get in? ⏰
Pacific local — shown in your device’s 12/24h format
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How long will you swim? 🏊
Drag the slider (10-minute steps) or type an exact time
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Pick a current prediction station 📍
One chart per spot - pick any - Alcatraz is usually a good start
Save this swim 🔒
Log in (free, no password) to save up to 3 swims and
jump back to them from the menu.
How to read this
- Splash
- The moment you enter the water and start your swim.
- Window
- The time range shown on the chart: your swim plus two hours of context on each side.
- Flood
- Incoming current, flowing east into the bay with the rising tide.
- Ebb
- Outgoing current, flowing west out of the bay with the falling tide.
- Arrow
- The small arrow on each stretch of the current line (one per flood, one per ebb) shows which way the water is moving: → east during flood, ← west during ebb.
- Slack
- The brief calm period between flood and ebb when the water barely moves — often the easiest time to swim.
- Knots (kt)
- Current speed. 1 knot ≈ 1.15 mph. Most swimmers move at 1–2 knots, so a 2+ kt current can dominate your swim.
- Bin / depth
- NOAA measures currents at several depths; the "bin" selects one. Deeper predictions are less accurate than near-surface ones.