I first heard of the Lost Sea back in early 2020. My husband, John, and I were dating at the time and he suggested we check out this underground lake not far from where he grew up, just south of Knoxville, TN.

Intrigued, I agreed it could be a fun day date. But then Covid happened and many of our adventurous date ideas were put on hold. This particular idea didn’t come to fruition till the day after Thanksgiving—in 2025.

With the day off and John’s cousin visiting from the UK, John pitched us on the Lost Sea Adventure instead of staying home or shopping on Black Friday. It felt like an easy yes, though we didn’t quite know what to expect—even John to some degree, since his last visit was probably 30 years ago.

Off we went on a chilly November Friday with temps in the 40s. Thankfully, the weather doesn’t matter when you visit the Lost Sea because the cave stays in the upper 50s all year round.

But wait. Cave? Let me back up.

What Is the Lost Sea Adventure?

According to TheLostSea.com:

Your Lost Sea adventure features a guided tour of the historic Craighead Caverns culminating with a boat ride on America’s largest underground lake.

The tour is a three-quarter mile round-trip that lasts about 1 hour and 15 minutes. During your visit, you will gain insights into the caverns’ captivating history and observe remnants of its past use by Cherokee Indians, Confederate soldiers, and a colossal prehistoric Jaguar from over 20,000 years ago. A voyage on the Lost Sea is sure to be an adventure you’ll never forget.

I can confirm that all of the above is 100% accurate—and 100% worth the trip!

And, in addition to the cave and boat tour, the Lost Sea grounds also include a gift shop in the main building, plus a small village (open seasonally) featuring a general store, candy and ice cream shop, glass blowing studio, and a picnic area.

My Experience at The Lost Sea

As I mentioned, I didn’t know what to expect. To be completely honest, I was skeptical that the Lost Sea would live up to the hype. Growing up, I remember plenty of “mystery spot” billboards and other signs for roadside attractions promising a one-of-a-kind experience for those who pulled over and forked over an admission fee.

In most cases, they were nothing more than tourist traps. Was this one of those?

NOPE.

The Lost Sea is absolutely not a tourist trap. It’s a massive cave system with a legitimate underground lake and guides who know the history well. Our guide, Spike, stopped periodically to share fun facts and point out geological details—like “cave flowers,” which are clumps of needle-shaped crystalline formations that resemble flowers and grow on cave ceilings and walls.

Along the trek down to the lake, Spike pointed out a section of graffiti left by Confederate soldiers during the Civil War. We also passed an underground waterfall and an old moonshine still once used down in the cave.

And then, the lake. After boarding a metal boat, we glided across the dimly lit underground lake. Spike fed the lake’s resident rainbow trout and told us how they got inside the cave. (Spoiler alert: the fish did not end up there naturally.) Overall, we spent 10-15 minutes on the lake before docking and hiking back to the cave’s entrance.

Yes, we hiked. Or at least it felt like a hike, because the way back is mostly uphill with a gradual incline. At the beginning of the tour, the staff do issue a disclaimer to anyone with a physical or medical issue who may not be able to complete the tour.

Click here to see a video of our experience.

Frequently Asked Questions (FAQs) About the Lost Sea

Is the Lost Sea worth it?

Personally, I believe it is, even with the general store and candy shop closed during our visit. The cave itself is a unique experience and kept my attention the entire time. And the boat tour on the lake was the perfect grand finale.

The entire tour also felt like just the right amount of time at just over one hour.

How much does it cost to get into the Lost Sea?

The Lost Sea website lists the following ticket prices (as of November 2025):

Adult: $28.95
Child: $16.95 (ages 4-12)
Senior $27.95
Military Adult $27.95
Military Child $15.95 (Ages 4-12)
Children 3 and under free.

Adult Annual Pass: $52.95
Child Annual Pass: $31.95
Family Annual Pass (2 Adults, 2 Children): $163.95

What should I wear to the Lost Sea Adventure?

Based on my experience, I recommend wearing:

Flat, comfortable shoes that you are okay exposing to a dirt path. Regular tennis shoes or sneakers are fine. Hiking shoes or boots are not necessary, but they would also work. (Note: The path is NOT muddy.)

Clothing-wise, wear anything you are comfortable walking in for 3/4 of a mile in approximately 58-degree weather. I saw people wearing anything from leggings and a sweatshirt to jeans and a nice sweater (me). Many people also wore coats, but mainly due to the temperature outside.

I wore a long sleeved tee, a chunky sweater, and my winter coat, and I was a bit warm. The cave also stays very humid, as evidenced by the level of frizz in my hair by the end.

Is the Lost Sea good for kids and families?

Absolutely yes. There were several kids in our group, along with people of all ages. The kids really seemed to enjoy the experience and were encouraged to ask questions.