Jill Hein­erth can proud­ly claim the title as the the world’s top under­wa­ter cave explor­er. She has dived in places no oth­er peo­ple have—including under deep Antarc­tic ice­bergs and through incred­i­ble under­wa­ter wrecks—and helped designed the first ever 3D map of an under­wa­ter cave. She’s also con­sult­ed for Hol­ly­wood and has pro­duced a num­ber of doc­u­men­taries and books. 

We talked to Jill about the dan­gers and rewards of extreme cave div­ing and why she keeps going back for more.

Jill photographs a fellow diver during an exploration project with the National Oceanographic and Atmospheric Administration (NOAA). Photo by Jill Heinerth
Jill pho­tographs a fel­low div­er dur­ing an explo­ration project with the Nation­al Oceano­graph­ic and Atmos­pher­ic Admin­is­tra­tion (NOAA). Pho­to by Jill Heinerth

The Clymb: How did you get start­ed in diving?

Jill Hein­erth: I want­ed to dive from my ear­ly child­hood, but grow­ing up in Cana­da, there were few oppor­tu­ni­ties that my fam­i­ly was aware of. I final­ly took a cer­ti­fi­ca­tion class dur­ing uni­ver­si­ty and com­plet­ed my open water div­er cer­ti­fi­ca­tion in Tober­mory Cana­da at Fath­om Five Nation­al Marine Park.

The Clymb: And how did things move from “reg­u­lar” div­ing to the extreme div­ing you do now?

JH: Almost imme­di­ate­ly I took the bull by the horns and moved rapid­ly through oth­er div­ing class­es and con­tin­u­ing edu­ca­tion. I was dri­ving up to Tober­mory most week­ends and with­in a cou­ple of years began instruct­ing scu­ba at the entry lev­el. I had such a pas­sion for div­ing that I soon sold my adver­tis­ing busi­ness in Toron­to and moved to the Cay­man Islands to dive full time. In the back of my head I knew I could find a way to com­bine both my pas­sion for div­ing and my cre­ative tal­ents. I got hooked on cave div­ing and moved to Flori­da to live in the most pop­u­lar region for cave div­ing in the world. It was in Flori­da that I began work­ing in film and tele­vi­sion projects asso­ci­at­ed with tech­ni­cal and cave diving.

The Clymb: You are an expert in one of the most dan­ger­ous sports in the world. Is that dan­ger part of the excitement?

JH: Most peo­ple assume that I must be an adren­a­line junky. I real­ly don’t think the sur­vivors in my sport fit that descrip­tion. I am actu­al­ly very risk averse. For me, cave div­ing and explo­ration are a great puz­zle. I love it when some­body asks me to do some­thing that has nev­er been done before or go some­place that has nev­er been explored. It’s not about the adren­a­line, but more about putting the pieces and the team togeth­er to make it hap­pen safely.


Preparing to descend on the deepest dives ever conducted on Bermuda. Photo by Nic Alvarado
Prepar­ing to descend on the deep­est dives ever con­duct­ed on Bermu­da. Pho­to by Nic Alvarado


The Clymb: Can you talk about a trip or cir­cum­stance when you’ve felt you were in danger?

JH: I’ve had numer­ous close calls in explo­ration. I was pinned down by rip­ping cur­rent inside an ice­berg cave in Antarc­ti­ca. I’ve been trapped on the wrong side of a cave div­er that was wedged tight in a body hug­ging restric­tion (the div­er became the cork in the bot­tle that con­tained my life). I’ve been tossed like a rag doll in six­ty foot seas and faced the busi­ness end of a rifle in a remote desert near the Libyan bor­der. But per­haps my worst scare was fight­ing off a bur­glar with an Xac­to knife in my home. In all those cas­es, I learned that you have to stuff the emo­tions back into some recess in your brain and main­tain ratio­nal, prag­mat­ic thought. You have to be able to take a deep breath and say, “emotions…you won’t serve me well right now,” and then get to the busi­ness of sur­vival. You might not know how every­thing will work out, but you can keep tak­ing baby steps towards sur­vival. Just do the next best thing.

The Clymb: Can you tell us what is like to dive under giant Antarc­tic ice­bergs? Is the expe­ri­ence very dif­fer­ent to div­ing any­where else?

JH: My Nation­al Geo­graph­ic Project to Antarc­ti­ca in 2000, allowed me to make the first cave dives inside ice­bergs. It was an expe­ri­ence of a life­time but per­haps one of the most dan­ger­ous things I have done. We trav­eled 12 days from New Zealand across the South­ern Ocean on some of the stormi­est seas on the plan­et. Nobody had ever dared to dive inside ice­berg caves before, so we were re-writ­ing the rules of engage­ment almost every day. On the final day of our project, after nar­row­ly escap­ing a ridicu­lous cur­rent that pinned us down inside a tun­nel in the ice­berg, the ice­berg we had just exit­ed calved and explod­ed. A huge square mile of ice was pul­ver­ized into slush in mere min­utes of destruc­tion. We had only just got­ten out of the water.

There was noth­ing like Antarctica…it was like trav­el­ing to anoth­er plan­et. I would return in a heartbeat.


Jill drives a digital wall mapper at Wakulla Springs. Photo by Wes Skiles, Courtesy of the U.S. Deep Caving Team
Jill dri­ves a dig­i­tal wall map­per at Wakul­la Springs. Pho­to by Wes Skiles, Cour­tesy of the U.S. Deep Cav­ing Team

The Clymb: What goes into extreme diving?

JH: Extreme div­ing takes end­less train­ing, lots of redun­dant equip­ment, and a cool head.

The Clymb: How is it dif­fer­ent from the fun sport that so many peo­ple asso­ciate div­ing with?

JH: Tech­ni­cal and explo­ration div­ing takes peo­ple beyond the realm of recre­ation. In recre­ation­al div­ing, you can always just abort a dive and swim straight up. In tech­ni­cal div­ing we are often in over­head envi­ron­ments like caves and wrecks and under an oblig­a­tion to decom­press our bod­ies before sur­fac­ing. If we swam straight up, we could get decom­pres­sion ill­ness or die. In some cas­es, the decom­pres­sion penal­ty can be extreme. My longest dive mis­sion was over 22 hours.

The Clymb: Is it just about envi­ron­ments or is it also about discovery/learning/etc.?

JH: For me it sat­is­fies a yearn­ing curiosity—about our plan­et and undis­cov­ered realms and also the depths of the human spirit…the abil­i­ty to face chal­lenges and embrace dis­com­fort, to explore some­thing that is mean­ing­ful to humankind. I often work with sci­en­tists on impor­tant projects look­ing at issues such as cli­mate change or evo­lu­tion or sur­vival of unique­ly adapt­ed ani­mal species.


Jill filming a BBC program where host Richard Hammond followed her team with a tracking device while they swam beneath Florida’s landscape in a network of cave passages.
Jill film­ing a BBC pro­gram where host Richard Ham­mond fol­lowed her team with a track­ing device while they swam beneath Florida’s land­scape in a net­work of cave passages.

The Clymb: Do you use any spe­cial­ized equipment?

JH: One of my spe­cial areas of focus is the use of rebreathers. These devices recir­cu­late your exhaled breath rather then dump­ing it in the form of bub­bles. The gas is sent through a breath­ing loop to a scrub­ber that removes car­bon diox­ide from the mix and adds minute amounts of oxy­gen that have been metab­o­lized by the div­er. It is the same tech­nol­o­gy that is used for mak­ing space­walks. We also use under­wa­ter scoot­ers called “div­er propul­sion vehi­cles (DPVs)” as well as high­ly tech­ni­cal cam­eras, map­ping devices, and oth­er sci­en­tif­ic sam­pling gear that can tol­er­ate the under­wa­ter environment.

The Clymb: You’ve earned some very impres­sive acco­lades, includ­ing being induct­ed to the Women Diver’s Hall of Fame and receiv­ing the Wyland ICON Award. Can you tell us a bit about these and oth­er prizes/mentions you’ve won?

JH: I was induct­ed into the Women Divers Hall of Fame in 2000. I’m real­ly proud of the orga­ni­za­tion that focus­es on offer­ing schol­ar­ships and train­ing grants to young divers look­ing to find their way in the under­wa­ter world. I am most proud of receiv­ing the first Medal for Explo­ration from The Roy­al Cana­di­an Geo­graph­i­cal Soci­ety. The medal rec­og­nizes life­time con­tri­bu­tions to explo­ration and I think it might have been the first time my par­ents real­ly under­stood that what I was doing with my life had real merit!


Jill photographs her partner as they exit a deep crevasse that leads to a cave system beneath a huge Antarctic iceberg. Photo by Jill Heinerth
Jill pho­tographs her part­ner as they exit a deep crevasse that leads to a cave sys­tem beneath a huge Antarc­tic ice­berg. Pho­to by Jill Heinerth

The Clymb: Of all the dives you’ve done, what would you con­sid­er the best/most excit­ing one you’ve ever done? What made it so special?

JH: That is a real­ly tough ques­tion…. Every dive has spe­cial mem­o­ries. I think per­haps the most life chang­ing project for me was the U.S. Deep Cav­ing Team Wakul­la Project. We made the first accu­rate 3D map of a cave sys­tem. The project was very deep and required some rev­o­lu­tion­ary thought. The team com­prised of 150 vol­un­teers who did every­thing from build tech­nol­o­gy to offer safe­ty div­ing sup­port. I had the oppor­tu­ni­ty to com­plete some div­ing goals that had nev­er been achieved by a woman…and per­haps less than a hand­ful of men. But what was far more impor­tant was the new under­stand­ing that I had with my water sup­ply. We not only mapped the cave in three dimen­sions, but we linked it to the sur­face topog­ra­phy accu­rate­ly. You could lit­er­al­ly walk over the sur­face of the earth and under­stand what was below your feet…a major drink­ing water sup­ply con­duit for the State of Florida.

After that, I began to focus all my atten­tion on projects that helped peo­ple bet­ter under­stand how what they do on the sur­face of the land would even­tu­al­ly be returned to them to drink. I have a unique oppor­tu­ni­ty to spread this “water lit­er­a­cy” as I call it and use my adven­tures to help peo­ple under­stand where their water comes from, how they might be pol­lut­ing it, and how they can pro­tect it for future generations.

The Clymb: Can you tell us a bit about the SEDNA Epic Expe­di­tion, its goals and how you got involved with it?

JH: The Sed­na Expe­di­tion began with a goal to cre­ate out­reach oppor­tu­ni­ties that helped peo­ple under­stand the issues of glob­al cli­mate change and how they were rapid­ly chang­ing the Cana­di­an North faster than almost any­where else on the plan­et. We also want­ed to cre­ate out­reach oppor­tu­ni­ties that helped the indige­nous com­mu­ni­ties of the north to bet­ter con­nect with their water resources. In 2014, we held a proof of con­cept expe­di­tion with an ulti­mate goal to snorkel the North­west Pas­sage as a relay of all women swimmers.

We trav­eled up the coast of Labrador and cut across the Davis Strait to Green­land and then on to Ice­land. Dur­ing the project we devel­oped the safe­ty pro­to­cols and tech­niques that would be need­ed to tra­verse the North­west Pas­sage in the future. I was the offi­cial under­wa­ter pho­tog­ra­ph­er on the project and was also brought along because of my cold water and expe­di­tionary expe­ri­ence. I helped train many of the women in aspects of dive tech­nol­o­gy as well as expe­di­tion man­age­ment and safety.