When Is the Next Negative Low Tide?

Understanding the Rarity and Timing of These Shelling Goldmines in SWFL

One of the most common questions we get from serious shellers is:

“When is the next negative low tide? I want to book a tour when the tides are at their lowest!”

We get it! Negative low tides can feel like striking gold for shellers—but here’s what you need to know:

What Is a Negative Low Tide?

A negative low tide means the water level drops below the average low tide line—literally below sea level. These extra-low tides expose areas of the sandbar and seafloor that are usually underwater, revealing fresh shell beds and hidden treasures that haven’t been picked over.

But here’s the catch… negative low tides are rare in Southwest Florida and very seasonal.

When Do Negative Low Tides Happen in SWFL?

You’ll only see negative low tides a few times per month, generally around the full moon and new moon, and typically only in winter and summer—and never at convenient midday times. Their timing flips with the seasons:

❄️ Winter:

• Negative lows occur near sunrise

• You’ll arrive on the island at the lowest point, but the tide rises fast the entire rest of the tour

• Great for early-bird shellers who want first dibs on what’s been revealed overnight

☀️ Summer:

• Negative lows occur near sunset

• You’ll start the tour with the tide still high, and then it will drop fast as the tour goes on

• Great for seeing new shell beds emerge right before your eyes

How to Track the Next One

Negative low tides shift a little every day—it’s not as simple as circling a date on the calendar. If you want to target one of these shelling sweet spots, here’s how:

✅ Use a tide chart app like Nautide. It’s my go-to app for checking daily tides, weather, and tidal coefficients.

✅ Look for tide predictions of -0.4ft or lower. That’s a strong indicator that areas of the sandbar will be fully exposed.

✅ Check the Tidal Coefficient. The higher that number, the bigger the difference between high and low tides—meaning stronger water movement, which can stir up and move more shells underwater. It’s a cool tool for predicting shell action even when tides aren’t negative!

✅ Don’t forget to check the TIME of low tide. A super low tide that happens at 3am or after sunset isn’t very helpful if you’re not shelling in the dark. Aim for low tides that line up with daylight hours or golden-hour tours.

✅ Best windows:

• December–February for early morning low tides

• May–July for late afternoon low tides

✅ Or—just contact us and we’ll help you find the next one that lines up with both nature and our tour schedule.

Should You Plan Around a Negative Low Tide?

Negative low tides are exciting, but they’re not the only time to find amazing shells. The islands we visit are naturally loaded with treasures year-round—we don’t need extreme tides to score big.

But if you’re someone who’s been dreaming of walking out further on the sandbar or seeing that hidden stretch of sea bottom, planning around one of these rare windows can be a special experience—just know you’ll have to work with nature’s clock and a bit of luck.

Want me to keep an eye out for the next good one? Contact me, and I’ll let you know when a promising low tide aligns with tour availability.

💡 Pro Tip:

Any time you see a Keewaydin Tour offered on my schedule, you can assume the tide will be at least -0.1ft or lower—because I only offer Keewaydin tours when the tide is right!