Can You Swim in The Lost Sea? The Hidden Truth

Let’s set off on a journey together to The Lost Sea in Sweetwater, Tennessee, the biggest underground lake in the U.S! We’re going to share all about it and even chat about if you can swim or dive there. So buckle up, we’re about to dive into a whole world of fun exploring this underwater wonder!

The Lost Sea: An Overview

The Lost Sea is in Sweetwater, Tennessee, USA and is part of a bigger place called Craighead Caverns.

It took millions of years for The Lost Sea to form. Nature did its magic through things like water washing away rock, dirt piling up, and the ground shifting. It’s like a big, natural art project that took a very long time to finish!

The Lost Sea is not your average lake. It’s underground and huge – over 4 acres! That’s about the same as three football fields. And it’s super deep, too. In some spots, it’s more than 140 feet deep. That’s taller than a 10-story building! Plus, it has something special called cave flowers. These aren’t like the flowers in your backyard. They’re rare and only found in a few caves in the world.

Source: Roadside America

Can I Swim in The Lost Sea?

The Lost Sea is super deep, over 150 feet, and it’s pretty cool, hovering around 58 degrees Fahrenheit. It’s big and chilly, which might make you think about jumping right in.

But hold your horses! It’s not safe to swim in The Lost Sea. The Lost Sea has invisible currents that can pull you under and the cold water might give you hypothermia. It’s dark and dangerous, so we need to stay safe and keep out of the water.

When Swimming in The Lost Sea is OK

There are some special times when people can swim in The Lost Sea. But it’s only for science or learning about the cave. These swimmers are pros and they always bring the right gear. But for the rest of us, it’s best to enjoy The Lost Sea from the safety of the shore.

So, even though it might look like a great place for a swim, The Lost Sea is off limits for your safety. We can still enjoy this underground marvel without getting our feet wet.

Read more: Can You Swim in Big Bear Lake?

Can You Dive The Lost Sea?

The Lost Sea is deep, dark, and cold. It’s more than 150 feet deep and not as welcoming as a usual diving spot. The darkness makes it hard to see and the chill can bite!

There are quite a few risks to consider. Imagine trying to find your way in a foggy street – that’s what diving in The Lost Sea is like due to poor visibility. The cold can cause hypothermia if you’re not dressed for it. Also, diving deep and coming up too quickly can cause decompression sickness, a serious condition that’s also known as ‘the bends’.

If you’re still keen, you’ll need some special gear. Think of dry suits to keep warm, dive lights to see, and a guide line to help you find your way. And don’t forget, you’ll need special cave diving training too.

Despite these challenges, some people like Bill Walter did dive here in the 1970s. His dive helped us understand more about this vast underground lake and its surrounding caves. But remember, diving here is not for everyone and needs careful planning and preparation.

The Fauna and Flora of The Lost Sea

The Lost Sea is not just a big lake, it’s a home. It’s where a rare type of blind cave fish lives. These little guys have learned to live in this dark, cold place. Pretty cool, right?

Now, imagine you’re swimming or diving in The Lost Sea. You might bump into these little fish. Sounds fun, but we need to be careful. Our fun shouldn’t bother these fishes or mess up their home.

When we swim, dive, or just hang out near the lake, we can accidentally hurt this delicate world. Even small changes can cause big problems. That’s why we always say, “look after nature.”

The Impact of Tourism on The Lost Sea

Every year, The Lost Sea in Sweetwater, Tennessee welcomes loads of visitors. People love to see America’s largest underground lake. It’s a real crowd-pleaser!

But, there’s a flip side. All these visitors can mess up the sea. Litter might get left behind, or the rare blind cave fish could get scared. It’s like having a party at your house and no one cleans up!

Also, the sea itself isn’t a safe place to mess around in. It’s deep, dark, and cold. If folks start swimming and diving without thinking, they could stir up trouble. Not just for them, but for the sea and its cool fishy dwellers.

So, what can we do? Well, we need to play it smart when visiting. We can limit how many folks come each day, make sure we don’t leave any trash behind, and say no to wild swimming and diving. It’s like going to a friend’s house – you want to be on your best behavior!

And let’s make sure everyone knows the rules. Don’t bother the fish. Don’t take any rocks home. It’s their home, not ours. By understanding and following the rules, we can all enjoy The Lost Sea without causing any harm.

Read more: Why Can’t You Swim in Reelfoot Lake?


The Lost Sea is a fascinating place but filled with challenges. The depth and cold temperature of the water pose a real risk. Safety guidelines are in place for good reasons. Swimming and diving here can be dangerous.

Our journey has also shown us the beauty of this unique ecosystem. We’ve learned about the blind cave fish and the rare cave flowers. We’ve seen how human activities can affect these delicate creatures and their home. We need to respect this place and work to preserve it.

The Lost Sea is a natural wonder that continues to captivate us. We encourage more exploration and study. But remember, it should be done with care. Let’s help keep The Lost Sea a mystery for future generations to unravel.