What Is The World’s Deepest Pool That Was Ever Recorded?

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In the early 90s, Belgian diving expert John Beernaerts had a dream to create a diving experience unlike any other in Brussels, Belgium. He knew there was quite a difference in learning to dive in exotic places like Bora Bora and learning in a boring pool somewhere. So he drew out his idea on a table mat for his friend, and it marked the beginning of his dream becoming a reality.

On May 1, 2004, 7 years and $5 million dollars later, Nemo 33, the first pool declared to be the world’s deepest pool was complete. Nemo 33 maintained its record as the world’s deepest pool until the Y-40 Deep Joy opened in Montegrotto, Terme, Pàdua, Italy in June, 2014.

Y-40 Deep Joy, which was designed by Emanuele Boarreto, took a year and a billion dollars to create. It features a shaft that plunges down to an unheard of 138 feet, which could accommodate a 13-story building. It is located inside the Hotel Terme Millepini in Italy and offers an underwater experience in its thermal waters that is unlike any other.

What Is the World’s Deepest Pool?

The Y-40 Deep Joy is located inside an Italian spa complex, the Hotel Terme Millepini, near Venice, and it is certified by the Guinness Book of World Records as being the world’s deepest swimming pool. Divers come from all over the world to enjoy this unique experience.At its deepest part, the pool is 138 feet, and there are also simulated underwater caves, platforms, and a suspended transparent viewing tunnel that allows visitors to watch the divers in action without having to get wet themselves. Swimmers can even recover after their deep diving experience on the sunbathing deck on the roof.

1) What Kind of Water Is in the World’s Deepest Pool?

The Y-40 Deep Joy has 4.3 million liters, or 1.1 million gallons, of thermal water from nearby springs. The waters are maintained at a temperature of 32-34 degrees Celsius, or 90-93 degrees Fahrenheit, at all times.

2) Is It Safe?

Yes. Safety is one of the primary concerns at the Y-40 Deep Joy. All activities and dives are supervised by certified instructors, most of whom are former world champions and record holders. One customer on Trip Advisor stated that it was like an underground theme park that was “so safe you could just relax and surrender to the water.”

3) Do Divers Have to Have a Wet Suit?

Due to the warm temperatures of the water to maintain their body temperature, divers can dive for long periods of time without a wetsuit in the world’s deepest pool.

4) Do They Have Equipment Available That You Can Use?

If you bring your own equipment, it has to be cleaned and certified before you can use it. This is to maintain the cleanliness of the water. The Y-40 Deep Joy does have equipment available for rental. On Saturday and Sunday, they do not allow you to bring your own equipment; you have to use theirs.

5) Does It Cost a Lot to Use the Facility?

Depending on what activities you want to experience at the world’s deepest pool, the cost ranges from 32 Euro to 115 Euro, which is around $36 to $130 USD, per activity. There are also packages available and packages for groups listed on the website.

What Is This Pool Used For?

Y-40 Deep Joy offers just that: joy for everyone who visits. It is used to instruct divers of every experience level and on many types of dives. It is also used for underwater activities such as swimming like a mermaid. It has also provided valuable information to many in the scientific and medical fields as they have studied the effects of water pressure on divers diving at various depths.

1) Diving Instruction

The Y-40 Deep Joy offers diving courses and workshops with many champion divers in their ‘pool hall of fame’. These record holders have joined the Y-40 Deep Joy team since it opened in 2014 and bring a unique perspective, as well as expert level experience, to their classes. They offer beginner to advanced classes year round.

2) Underwater Activities

Do you know anyone who would like to be a mermaid? They can do that here at the world’s deepest pool, and so can you. Freestyle divers, ages 6-13, can learn how to swim like a mermaid or a dolphin thanks to Italian free-diving champion Ilaria Molinari and her staff. Ilaria also offers an adult class as well: ‘Become a Mermaid’. This class focuses on body tone and shaping.

3) Scientific and Medical Experimentation

More than 60 centers of underwater medicine and hyperbaric research have done experimentations in the depths of the Y-40 Deep Joy since it opened. Universities, scientists, and medical research centers have studied the effects of water pressure on the human body.

4) Weddings

Yes, you read that right. Weddings. As of 2017, there have been two weddings performed in the depths of the world’s deepest pool.

5) Underwater Film and Photo Shoots

The Y-40 Deep Joy allows and encourages underwater filming and photography, hence the many beautiful photos and videos available online for your viewing pleasure.

How Can You Swim in This Pool?

Taking a trip to Italy is certainly not a bad idea on any given day, but if you want to swim in the world’s deepest pool, you will have to plan your trip to get there. The Y-40 Deep Joy is open Monday through Sunday and closed on major holidays.

Their user-friendly website can be used to help you decide on your visit, hotels, flights, and rentals. Remember that for diving, children must be 8 years and up: but there are a few activities for children 6 years and up. Medical forms and certifications are also necessary for some dives and activities.

1) Plan Your Trip

Decide when you would like to go to the Y-40 Deep Joy and explore their website to get an idea of what is going on there during that time. By getting an idea of what activities are available and when, it will be easier to plan your trip and what you plan to do when you get there. The website also shows how to get to the world’s deepest pool by plane, by train, and by car, so whether you live close by or thousands of miles away, you will be ready to get there.

2) Sign Your Informed Consent

Before you are allowed to swim in the world’s deepest pool, you will need to fill out your informed consent that they will store on file for a year. This form must be filled out for both adults and minors as it gives detailed instructions and consents for the activities that will be carried out. This is required by the consumer protection regulations.

3) Choose Your Activities

Once your consent is done, you can then pick out the activities that most interest you and your family. Whether you want to freestyle dive, scuba dive, go snorkeling, become a mermaid, or a number of other fun things, you can find the date and time that works best for you. Be sure to visit the Y-40 Deep Joy Facebook page too. It is extremely helpful because it lists the events and classes that are still open and the ones that are sold out.

4) Make Sure You Have the Certifications You Need

Each level of diving instruction from beginner to most advanced is listed on the website. When you click on each one, they show you whether a certification or medical certificate is necessary for that particular dive. Make sure to do your homework so you will know what you need to have before you go. You can also speak with the staff by phone or in person so they can assist you.

5) Enjoy

Once you have arrived at the Y-40 Deep Joy and have all the appropriate paperwork filled out, grab your gear, or rent theirs, and just enjoy your experience. The thermal water is unlike anything you will ever experience, and the opportunity to dive and take classes with world champions is not something you get to do every day.


While the thought of diving 42 meters, or 138 feet, down into the depths of the world’s deepest pool may be scary for some, more and more people do it every year. Of course, it helps ease some of the fear when you consider that the certified instructors supervising those swims and dives are former world champions.

Then, add the thermal waters that allow you to leave the wetsuits at home, the numerous underwater activities, and the uniqueness of the overall experience at Y-40 Deep Joy, and we have concluded that the world’s deepest pool should be on everyone’s bucket list.

Whether diving is a passion of yours or something you have always wanted to try, an opportunity to do so in the world’s deepest pool would be an experience unlike any other, and we would encourage anyone to go for it.

Featured image by David Yu via Pexels.

Jack Thompson

Jack Thompson, a scuba diving enthusiast from San Diego, has spent over a decade exploring the underwater world across the globe. Sharing his passion through captivating stories and informative articles, Jack aims to inspire others to embark on their own scuba diving adventures and uncover the ocean's hidden treasures. Follow Jack on Twitter, Pinterest, Reddit, and Facebook or email him at Jack@diving-info.com

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