Inspire a lifetime of ocean adventure and stewardship.

Celtic Deep is a social enterprise run by marine biologists and freedivers, offering in-water wildlife experiences in the offshore and island habitats off the coast of Pembrokeshire.

From swimming with blue sharks to snorkeling among the puffins of Skomer Island, Celtic Deep uses low-impact, high-value experiences to capture imaginations and unveil the wonders of Welsh marine life. These trips also inspire Celtic Deep's wider outreach efforts.

Where it all began

The Celtic Deep, a 100-meter deep depression in the seafloor 30 miles off Pembrokeshire’s coast, is home to some of the UK's most awe-inspiring marine life.

It was here that in 2018, Richard Rees led a group of friends (some more convinced than others) offshore, out of sight of land. The pledge was of swimming with blue sharks.

It was October; late season, and although the group was rewarded with an exhilarating glimpse of a blue shark, a minke whale and hundreds of dolphins, the story of the day was bluefin tuna ‘the size of cows’ busting right next to the boat.

So unexpected and outsized were these creatures, that it took a moment to decide what they were. For a group of Pembrokeshire locals, it was as if they’d been transported through a portal to a different world.

Witnessing this, just off our doorstep, convinced us there were many more adventures to be had—and shared.

Changing perceptions

Back on land, the response to these early adventures shaped what Celtic Deep would become.

Sharing these experiences revealed their power to change how people perceive our waters. These were Blue Planet-worthy species: giants, icons, and the largest in the world. In Welsh waters.

Tales from the Deep could ignite imaginations, challenge the perception of our seas as “too cold, nothing-to-see” and inspire a new appreciation for our marine ecosystems.

Commitment to the Deep

Celtic Deep is committed to the belief that wildlife tours, especially those seeking vulnerable species in hard-to-reach areas, have a responsibility not just to minimise their impact, but to add value.

Alongside providing fun, safe, informative experiences, we have set ourselves the following commitments:

  • Conducting research and hosting researchers

  • Providing early career opportunities

  • Giving access to young people and disadvantaged groups

  • Assessing our own impact and setting a sustainable precedent

  • Sharing our findings with the community

  • Advocating for the protection of the Celtic Deep

We love sharks

If any group of animals needs more awareness and appreciation, it’s sharks. In Pembrokeshire, attitudes often mirror Jaws-inspired fears—or surprise that sharks even exist in local waters.

Celtic Deep unapologetically champions sharks. As lynchpin species, they shape and maintain healthy ocean ecosystems. Yet decades of vilification have led to fear, apathy, and exploitation.

Approximately 100 million sharks are killed annually, and 70% of pelagic shark populations, including blue sharks, have disappeared in the last 50 years.

Swimming alongside a shark is humbling and inspiring. It connects you to millions of years of evolution and underscores the stark reality of their plight.

We know we can’t take everyone on our boat, but it only takes one person to love a shark for an entire family or community to reconsider their narrative.