World champion freediver Marina Kazankova is on a mission.

To free dive the Great Barrier Reef, taking on a series of challenges, from swimming with turtles and giant groper, to diving on ship wrecks and through awesome caves.

One challenge at a time, all on a single breath of air.

Capable of holding her breath for 7-minutes at a time, Marina travels to the iconic Heart Reef, swimming around both its outer coral walls, and along its inner lagoon.

She takes on raging horizontal waterfalls, swimming through boiling waters surging out of coral lagoons.

And she encounters a giant whale shark, swimming freely alongside it for long periods.

From freeing trapped sea birds to following turtles as they lay hundreds of eggs, Marina experiences the very best of the Great Barrier Reef.

Her journey takes her from the Hardy Reef, off the Whitsunday Islands, way south, exploring coral cays, and encountering an array of vibrant coral formations and dazzling sea creatures.

All of this, as the full moon triggers the spawning of coral, a phenomena that Marina experiences on a series of night dives.

Filmed on glorious 4K, ULTIMATE FREEDIVING: THE GREAT BARRIER REEF is being edited now, timed for a release at MIP in Cannes this April.

6 cameras follow her every dive, from drones above to a series of cameras beneath the waves.

And what they capture shows an impressive series of challenges that brings Marina face to face with the very best of the Great Barrier Reef’s corals and creatures.