Prehistoric spring and dive site

Devil’s Den Prehistoric Spring

About 2.8 miles straight-line from Kirby Family Farm

A 72-degree underground spring in a 120-foot-wide cave, open to reserved strong-swimmer snorkeling and certified buddy scuba—not general swimming or a casual dry-cave tour.

The place

About Devil’s Den Prehistoric Spring

Devil’s Den is one of Williston’s defining natural attractions, but it should be planned as an active-water appointment rather than an ordinary sightseeing stop. The privately operated spring sits inside a 120-foot-wide cave and remains about 72 degrees year-round. The operator connects the site to Pleistocene fossil discoveries, while asking visitors not to touch or remove rocks or fossils.

Snorkeling is a 90-minute reserved session and costs $30 per person. A $5 nonrefundable deposit is charged in advance, with the remaining $25 due on arrival. Mask, snorkel, and fins are mandatory but not included; visitors can bring their own or rent a $15 bundle. Snorkelers must be strong swimmers, arrive at least 15 minutes early, and complete waivers.

Certified scuba divers pay $48 and need an open-water certification or higher plus a buddy throughout the dive. Ordinary scuba does not require a reservation, although night dives do. The operator prohibits cave entry and several equipment configurations for recreational divers. Last entry and out-of-water rules protect the closing window.

There is no general swimming in the den. A separate $15 walk-through/day pass does not include den entrance. Children under 6 cannot access Devil’s Den, and every minor needs a parent onsite or the operator’s notarized consent process. No sunscreen is allowed. Those constraints make this a poor spontaneous add-on but a strong deliberately planned second day.

What stands out

Underground spring chamber

Natural light enters a cave over a clear 72-degree pool rather than an outdoor swimming beach.

Snorkel without scuba certification

Strong swimmers can reserve a 90-minute snorkel session with mandatory equipment and waivers.

Certified scuba access

Open-water divers can enter with a buddy while following site-specific restrictions and no-cave-entry rules.

Pleistocene setting

The operator interprets fossil discoveries and prehistoric geology without allowing visitors to remove material.

Pair it with the train

Why it belongs in a Kirby Family Farm trip

Devil’s Den is about 2.8 straight-line miles from Kirby. Pairing both on the same day is realistic only with a confirmed water session, adequate changing and travel time, and no conflict with the farm event’s gate or first-train window.

Before you go

Plan your visit

  • Snorkeling$30 for a 90-minute reserved session; mask, snorkel, and fins required. $5 nonrefundable deposit, then $25 on arrival.
  • Scuba$48 for certified open-water divers or higher. A buddy is mandatory; ordinary daytime scuba does not require a reservation.
  • HoursGate open daily 8 a.m.–5 p.m.; snorkel slots Mon–Thu 9 a.m.–4:30 p.m. and Fri–Sun 8 a.m.–5 p.m. Holiday closures differ.
  • AgeChildren under 6 cannot access the den. Minors require a parent onsite or the published notarized-consent process.
  • Swimming abilitySnorkeling requires a strong swimmer. General swimming and ordinary flotation devices are not allowed.
  • EquipmentSnorkel rental bundle is $15. Scuba rental options are separate. Confirm fit, availability, and current restrictions.
  • Environmental ruleNo sunscreen is allowed. Do not touch or remove rocks or fossils.
  • LodgingThe property publishes tent and RV camping plus four cabins sleeping four; lodging has separate reservations and terms.

Appointment-only alternative

Add Two Tails Ranch

Trade the active-water session for a scheduled educational elephant tour when swimming, certification, or age limits do not fit the group.

View the guide →

Useful answers

Frequently asked questions

Can I visit Devil’s Den without swimming?

A $15 walk-through/day pass is published, but it does not include entrance to the den. Spring access is limited to snorkelers and scuba divers.

Do I need a snorkeling reservation?

Yes. Snorkeling uses a reserved 90-minute slot and a $5 nonrefundable deposit.

Do I need scuba certification?

Yes for scuba. The operator requires open-water certification or higher and a buddy at all times. Snorkeling does not require certification but does require strong swimming.

Can young children enter?

Children under 6 cannot access Devil’s Den. Additional parent or notarized-consent rules apply to all minors.

Can I wear sunscreen?

No. The operator prohibits sunscreen to protect fish and turtles.

Trust and accuracy

Sources

Source checked 2026-08-14. This free guide has not yet been confirmed by the venue. Current hours, prices, services, and accessibility can change; confirm time-sensitive details directly.