William, let’s start from the beginning. What names and experiences shaped the athlete you are today?
“Everything started with the images from Le Grand Bleu; that film left a deep mark on me. Growing up on a boat, freediving was part of my everyday life, even though I didn’t yet consider it a sport. Awareness came in 2002, when I discovered the names Pelizzari and Pipin. The following year I decided to enroll in a course with Umberto, in Sardinia: I stayed there to train, learn Italian, and officially kick off my career.”

Why did you choose CNF (Constant Weight No Fins) as your discipline of choice?
“For me, CNF is the purest expression of human potential. Almost all water sports take place on the surface, exploiting the speed of air, or use water for propulsion like in swimming, where what happens above the surface is fundamental. Even in synchronized swimming, the action is seen from the outside and the entire performance requires breathing several times. Freediving, on the other hand, is the only discipline in which the action is 100% underwater. In No Fins in particular, you feel everything: the glide, the pressure of the water on your hands and feet. It’s an intimate dance with the element, a holistic discipline that connects you totally with the sea. There is no equipment or performance gear. It’s just you and the element.”

Speaking of your Italian roots: in 2003 you trained with Umberto Pelizzari and later helped translate the Apnea Academy manuals. How did such a relaxation- and diaphragm-centered style influence your technique, considering that CNF is extremely physical?
“Becoming an instructor in 2004 and working on Umberto’s texts helped me understand how to pass this sport on. Apnea Academy’s concepts of breathing and relaxation remain the foundations I still teach today, because they are often missing even in experienced freedivers. That said, I added some personal, more ‘extreme’ elements to go beyond 100 meters: I was among the first to introduce specific lung stretching, reverse packing, internal massages, and advanced pranayama. I tried to create a protocol to intensify the Mammalian Dive Reflex (MDR) and trigger it earlier. The faster we enter blood shift, the more oxygen we preserve. By using tongue blocks or bandhas to avoid contractions, we can optimize physiology. It’s an approach I tested scientifically and now teach in my courses.”

The Italian approach of those years is often seen as “romantic” and instinctive. You, on the other hand, seem almost like an engineer of movement. How do you reconcile these two visions?
“I consider Pelizzari a mentor and Jacques Mayol a sort of spiritual ‘grandfather.’ I still remember my first year in Sardinia: I was passionate about underwater breaststroke, but at the time it wasn’t a discipline considered in world championships. I asked Umberto, ‘Can I do a breaststroke dive?’ He looked at me puzzled: ‘Why would you want to do something like that?’ He followed me down to 38 meters, thinking it was a whim, but over the years he understood the importance of that intuition. Without a spiritual relationship with the sea, freediving cannot last over time. At the same time, I consider myself a performance scientist: I analyze every detail, from nutrition to periodization. Freediving is like a set of ten plates that must all keep spinning at the same time (hypoxia, technique, relaxation, flexibility, etc.): if one slows down, it ruins the entire performance. In land sports, the main aspects are usually five or at most seven; in freediving there are ten, all essential—without them, you simply can’t make a good dive.”

You developed the concept of the “Mental Immune System.” What happens in your mind when narcosis sets in deep down, in the darkness of Dean’s Blue Hole?
“The sea taught me the technique of the Observer Mind. It’s a pearl I found in the depths and try to bring to the surface for everyone. During preparation, negative thoughts arise. If we react emotionally, we lose relaxation and the dive is compromised. We must refrain from over-desiring the breath and understand that we are not what we think. In fact, the more intensely and earlier we activate blood shift, the more oxygen we preserve. CO₂ levels should not be reduced through hyperventilation—perhaps due to anxiety or stress—because CO₂ becomes a precious travel companion that allows us to maximize metabolic efficiency processes. The trick is understanding that thoughts are not ‘ours’; they are just contents of consciousness. Imagine being in a muddy river and struggling to keep your head above water: the Observer Mind is the ability to step aside, sit on the riverbank, and watch the river flow with detachment. At 60 meters deep, sometimes I stop perceiving time and emotions: I remain only a point of pure consciousness without a body. Freediving gives you this state of grace. It’s not just about staying calm, but about having an active response to stress.”

Let’s change topic. World records seem to be approaching a physiological limit. Will we ever see the end of new records?
“Competition is inherent to human nature—we always want to challenge ourselves. I tried to live the challenge against myself and my own records, which is healthier than fighting against others. From this point of view, I consider myself lucky. Today, top-level athletes are no longer limited by equalization, but by hypoxia and the risk of decompression illness (DCI). In the last ten years, records haven’t improved as dramatically as they did between 2000 and 2010. We’re approaching a very hard-to-break threshold, but we’ll keep trying.”

Any news on Vertical Blue?
“For 2026 we have ‘top secret’ plans. I prefer not to talk too much about my personal goals, so as not to disperse motivational energy. When you share your dreams too much, the people who care about you already reward you with wishes and kind words. This risks suffocating motivation by prematurely reaching a sort of emotional reward. As for the event, this year we’ll host a smaller competition for logistical reasons (the island’s main airport is closed). But in 2027 we’ll be back ‘in a big way’: 42 athletes, the Dive Eye system, and a massive production.”

How do you see the future of freediving?
“I see more and more people becoming passionate about this sport, and that makes me extremely happy, because the more people enter the sea, the more there will be those who take care of it, developing sensitivity toward it. On the other hand, I can’t help noticing a new trend focused more on ego and followers, where freediving is treated like any other sport, without real care for the environment we dive in or for our own bodies. For many years, this kind of mindset was external to the freediving world; the fact that it has managed to enter saddens me greatly. However, if the approach to our sport remains the traditional one—of people in love with the sea and with this practice—we’ll manage to keep our beloved discipline pure.”

Many associate you only with depth, but how important is indoor training to you?
“Very important. I calculated that I’ve covered about 6,000 kilometers underwater during my career. In the pool, you train basic technique. I reached 186 meters in DNF (Dynamic No Fins) and 211 meters in training, despite having normal lung capacity—unlike champions like Malina, who have enormous lungs. Depth is the ‘great equalizer’: there, it doesn’t matter how big you are, but how hydrodynamic and precise you are. An overly loaded lung brings several disadvantages, both on descent and ascent. Becoming negative too late requires greater effort to reach the neutral phase of the dive, while adding more weight to become negative at shallower depths results in an ascent with a heavier load to carry.”

Will we see you in Italy again soon?
“I’ll definitely be back next year! For those who want to train with me, I work with very few people at a time (maximum four) in 1:1 pathways, or there’s my online platform with over 80 technical videos on lung stretching and training. You can find links and content on my Instagram profile. One last simple piece of advice for beginners: rely on good teaching, but never stop experimenting on yourselves and sharing sensations with your dive buddies.”