A freediver descending head-first along the line into deep blue water

Freediving instructor · Ranked athlete · Dominica

Fall calm,
rise strong.

The UK's deepest no-fins freediver. 8th in the world. AIDA Master Instructor, based in Dominica.

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Photograph · Daan Verhoeven
I · The surface

On one breath

About Harry.

Long before the deep, there was the river — a Winchester College First VIII oarsman at fifteen, a GB Rowing trialist. And before the ocean, the deep he loved was overhead: an astrophysics undergraduate whose first vast, silent place was the night sky.

Then, locked down in Hawai'i during Covid, Harry took a breath and went underwater. That hobby became a calling. Back in the UK in 2020, a friend brought him to a depth camp in the cenotes of the Yucatán; those days with Johnny Sunnex left an indelible mark. By 2022 he was on his way to Dominica — a volcanic island ringed by deep, clear water — and committed completely.

In the early days it was just about getting in the water with friends to escape quarantine, but as I followed the wet breadcrumb trail — it kept giving back.”— Harry McCahill
Harry McCahill freediving down toward a shipwreck in the deep blue off Hawai'i The early days, diving the wrecks of Hawai'i with Will Melville
II · The descent
Cenote Ucil — a sunlit cavern pool in the Yucatán, Mexico, with wooden steps down to clear blue water Exploring Ucil — the heart of the Yucatán

Exploration

New water,
new depths.

Before the competition line, the pull was exploration. The cenotes of the Yucatán, Dean's Blue Hole of the Bahamas, the shores of South Africa and Cornwall — walls and caverns and open blue, each new water was novel; the practice wasn't the centrepiece yet.

Every new place opens a quieter one. With no sound, no weight and nowhere to be, the descent turns inward — the deepest water Harry knows is the stillness of his own mind, somewhere only a held breath can reach.

Adventure drives me — I love to see new places, have new experiences, meet new people. But what I couldn't know was the adventure freediving would take me on inward. That is the real gift.”— Harry McCahill
A no-fins freediver gliding weightless, arms spread, in a column of light from the surface

III · The deepest point

The competitor

8th in the world,
in the purest discipline.

Hobby becomes devotion. Competing only since 2024, Harry is the deepest no-fins diver in Britain and holder of three national records — in Constant Weight No Fins, where a diver descends and returns on a single breath using nothing but their own body.

In 2026 he earned a wild card to the AIDA Depth World Championships in Limassol, Cyprus.

Photograph · Allie Reilly
IV · The ascent

The mindset

The hardest metres
are the last.

The ascent is where a dive is decided. The urge to breathe arrives, the body begs to rush — and the discipline is to stay slow, stay soft, and trust the work already done.

You don't fight the pressure. You meet it — one relaxed pull at a time — and let the surface come to you.

I have learned more about the power of positive self-talk in these metres than in all the years of my life.”— Harry McCahill
Freedivers rising up the line from the deep at Dean's Blue Hole, Bahamas, during Vertical Blue 2025 Rising up from Dean's Blue Hole, Bahamas at Vertical Blue 2025
V · The coach
Harry McCahill in a wetsuit on the shore of Soufrière Bay, Dominica Soufrière Bay · Dominica Allie Reilly

The coach

Calm is taught,
not forced.

As an AIDA Master Instructor, Harry has certified 120+ students — from first breath-holds to competition depth. The approach is the same calm that defines his own diving: relaxation, efficient technique, and nervous-system regulation. Not pushing.

  • AIDA courses, beginner to instructor — year-round in Dominica
  • Depth coaching & competition preparation
  • One of the world's premier depth-training locations: deep, warm, still water
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VI · The surface again

Rise strong.

Train with Harry in Dominica, partner with a rising GB athlete, or just follow the story — one breath at a time.

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