Blue Planet III, on BBC One and iPlayer, ventures deeper beneath the waves as David Attenborough reveals ocean life more surprising, more intelligent and more precious than we ever realised.
The Blue Planet, the first ever natural history series to give a comprehensive overview of the world’s oceans, was broadcast across the globe 25 years ago. In 2017, Blue Planet II galvanised a global movement to rid our oceans of single-use plastic and revolutionised how we see life in our oceans. But this was only the beginning…
Our Blue Planet III episode guide explores tropical seas, open oceans, seasonal seas, polar waters and the deep, taking us around the world and back again. Speaking about the third series of this groundbreaking BBC show, Executive Producer Elizabeth White said, “The Blue Planet was an unbelievably cutting-edge series that captivated audiences because it was the first time we’d really seen the spectacles of the underwater world in a big, blockbuster landmark way. Seventeen years later, Blue Planet II leaned into science and discovery, showcasing how much our understanding of the oceans had evolved and the growing environmental challenges facing marine ecosystems. With Blue Planet III, we wanted to build on that legacy.
In making Blue Planet III, we had three ‘pillars’: closer, deeper, and more connected. We wanted people to really empathise with and relate to these animals. I think the ocean is often thought of as somewhere that invokes awe and wonder, and sometimes fear. I think we were trying to move beyond that, to be a place where, even though some of these animals may have scales and slimy bodies and their eyes are on the side of their head, actually, they’re really endearing and relatable!
It’s also a new Blue Planet for a new generation. As a mother of two small children, I’m seeing firsthand how many young people experience and engage with natural history through series like this. I’ve met countless people who say the past series had a huge influence on them. Launching a new series gives us a chance to capture the hearts and minds of a whole new generation.”
Image: BBC Studios/ Anoushka Freedman
Episode One: Tropical Seas
The warm, sunlit waters of the tropics support the ocean’s greatest diversity of life. Yet even in these seemingly familiar seas, astonishing new behaviours are still being discovered.
At the northern tip of Australia, tawny nurse sharks appear to work together to herd fish onto beaches before vacuuming up their prey. Nearby, bottlenose dolphins have revealed a hunting technique new to science, using sea sponges to block holes in coral reefs where fish go to hide – one of the most sophisticated examples of tool use ever documented in the animal kingdom.
Across the tropics, coral reefs bustle with life. In the Red Sea, coral groupers team up with giant Māori wrasse and moray eels to flush prey from the reef’s maze of crevices, while after dark in Bali, tiny harlequin shrimp take on starfish many times their size.
Beyond the reefs, humpback whales arrive after epic migrations from Antarctica. For one female, this will be her final journey, as her death brings life to one of the tropical ocean’s most barren landscapes.
On the remote island of Fernando de Noronha, green turtles must evade tiger sharks, while in seagrass meadows and mangrove forests, dugongs, remoras and fiddler crabs navigate lives shaped by risk and opportunity.
But the tropics’ future is increasingly uncertain. In the Coral Triangle, an unprecedented marine heatwave causes corals and sea anemones to bleach, threatening the home of a clownfish family fighting to survive. From discoveries to spectacular wildlife drama, Tropical Seas reveals the beauty, ingenuity and resilience of life in the richest seas on Earth.
Speaking about episode one of Blue Planet III, Producer Yoland Bosiger said, “The tropical seas are the warmest of our oceans. They are often clear and calm, and they evoke in many of us an image of white-sand beaches and palm-fringed shores – a perfect paradise where one might dream of swimming on holiday. But these seas are so much more. In episode one, we explore the extraordinary variety of habitats that are found in the tropical seas, from coral reefs to seagrass meadows and mangrove forests to remote islands. These habitats support animals of all shapes, colours, and sizes – in fact, tropical seas are home to the greatest diversity of species in the ocean.
What makes this part of the ocean so fascinating to me is the remarkable intelligence of the animals that live there. Across the tropics, the greatest concentrations of life are found in hotspots scattered among vast expanses of sand and mud. These hotspots can be intensely crowded and competitive, so to get by, animals often lead highly complex lives – some with surprising parallels to our own. Tropical Seas takes audiences beyond the familiar image of paradise to reveal a world far more complex, surprising, and vulnerable than it might first appear.”
Episode Two: Open Ocean
The Open Ocean is Earth’s largest wilderness. Covering more than half the planet, it looks like an endless blue desert. Yet beneath its vast surface lies a world of extraordinary life, where survival depends on endurance, tenacity and teamwork.
Far from land, California sea lions venture deep into the Pacific to join one of the ocean’s great feeding spectacles, as tuna, mahi-mahi and seabirds converge on vast shoals of fish in a dramatic battle to feed.
While many animals pass through these waters on epic migrations, others spend their entire lives in the vast blue expanse. Among them are rough-toothed dolphins, a species that has roamed the oceans since before the time of the mammoths. Little understood, they rely on sophisticated teamwork to thrive in a world where food can be hard to find.
Though seemingly featureless, the Open Ocean is shaped by powerful currents that flow around the globe like invisible rivers, transporting animals, nutrients and entire ecosystems across immense distances. These currents sustain life but can also carry it into danger.
In the Atlantic, changing conditions are sweeping unprecedented amounts of sargassum seaweed onto Caribbean coastlines, creating new challenges for wildlife, including newly hatched turtles struggling to reach the sea through vast mountains of stranded sargassum.
In a breathtaking finale, killer whales attempt to hunt an adult blue whale, an extraordinary encounter between the largest animal ever to have lived and one of the ocean’s most formidable predators. Together, these stories reveal new insights into the drama of life in Earth’s greatest wilderness.
Episode Two Producer Natasha Fellows said, “The Open Ocean episode takes us beyond the coast and out into the ‘big blue’, the endless expanse of water that you see when you stand on a beach and look to the horizon. It’s a vast wilderness, often hundreds or thousands of metres deep. Many superlatives could be used to describe it – I like the fact that it covers over half of our planet. But, despite its scale, we still don’t know that much about it. One key idea I wanted to convey in this episode is that the open ocean isn’t just a vast space of nothingness, as it often seems. There is actually a lot of life here, if you know where to look.”
Image: BBC Studios
Episode Three: Seasonal Seas
Sitting between the tropical and polar oceans, the Seasonal Seas are among the most changeable waters on Earth. Here, life must endure fierce winters, violent storms and scorching summers, pushing animals to be resourceful, adaptable and adventurous.
In Chile, some of the boldest South American sea lions travel up to 30 miles upriver to hunt swans, while southern right whales battle through the planet’s roughest seas to reach sheltered breeding bays, where many give birth to dazzling white calves.
As spring transforms these oceans into some of the most fertile waters on Earth, hundreds of millions of crabs gather to feast in spectacular feeding frenzies. Vast underwater forests burst into life, becoming arenas for fierce mouth-to-mouth battles between bright orange female eelpouts competing for mates.
Summer brings new challenges. In Japan, an octopus risks her life by leaving the water to hunt on land, racing to reach the sea before she dries out beneath the relentless sun.
But the greatest force reshaping these seas is increasingly human activity. In Portugal, the loss of seagrass meadows forces a seahorse to cross barren sandflats to find a mate. Yet there is hope. Thanks to conservation measures, wildlife is returning to places once thought lost. In the waters surrounding New York City, sharks, dolphins and humpback whales are making a remarkable comeback.
Filled with surprising new behaviours and stories of resilience, Seasonal Seas reveals how life thrives in one of the ocean’s most dynamic environments. Speaking about discoveries or filming firsts, Episode Three Producer Joanna Haley said, “One of the things I love most about making wildlife documentaries is filming behaviour that no one has ever captured before. I always try to push to find new stories.
Filming sea lions travelling 30 miles upriver to hunt swans was a perfect example. The team worked from a small boat in the depths of winter, with no shelter from dense fog and six hours of freezing rain each day. Over the four-week shoot, only a handful of days saw the rain subside long enough for a proper filming opportunity. And then, the rare behaviour had to happen in just the right place.
The wetland where the swans live is enormous – around 60 km² – and only a handful of sea lions had learnt to catch them. So the chances of a hunt happening close enough to the crew were tiny. The wetland was also full of submerged trees, so when the tide was low it was almost impossible for the crew to follow the sea lions, who could weave their way easily through the branches.”
Episode Four: Polar Waters
Though they lie at the ends of the Earth, the polar seas help drive a global network of ocean currents that shape life across the planet. From Antarctica and the Arctic come powerful flows of water which transport oxygen and nutrients around the world, creating extraordinary opportunities beneath the ice and supporting wildlife far beyond it.
In Japan, a male dwarf lumpsucker, no bigger than a pea, makes a nest in cold-water currents and guards his eggs day and night against hungry predators.
Around Antarctica, hundreds of fin whales converge on one of Earth’s greatest feeding grounds, working together in spectacular synchrony to feast on dense swarms of krill. Beneath the sea ice, a hidden world flourishes, where giant sea spiders roam ancient glass sponges and tiny amphipods hitch rides on jellyfish and sea angels to evade danger.
The polar waters are so important that they help power our global currents, bringing Atlantic bluefin tuna to the coast of the UK. But when they fail, animals must adapt: in the rapidly warming Gulf of Maine, puffin parents struggle to feed their chicks.
In Svalbard, change is creating new opportunities as a young polar bear encounters unfamiliar prey. From the icy worlds of the poles to unexpected coasts closer to home, Polar Waters reveals the surprising connections between the world’s oceans and how animals are adapting in the face of change.
Speaking about some of the more exciting sequences filmed, Series Producer Lara Bickerton said, “I love the high-tension sequences, like the tiger sharks hunting turtles and the incredible sea lion and penguin hunt in the Polar Seas episode. They’re both edge-of-your-seat sequences that showcase the drama of life in the ocean. At the same time, some of the more unexpected and comedic stories are just as memorable. The dugong sequence makes me laugh every time, and the crab sequence is just wonderful – the musical score elevates that story perfectly, giving it a real sense of majesty and wonder.”
Image: BBC Studios
Episode Five: The Deep
A journey into Earth’s last great frontier. Hidden beneath the ocean’s surface lies a vast and largely unexplored world of deep coral reefs, underwater mountains, volcanoes and hydrothermal vents, home to some of the most extraordinary discoveries of our time. As new technology takes us deeper than ever before, astonishing creatures and entire ecosystems are revealed in spectacular detail.
A tiny argonaut, no bigger than a pea, embarks on the planet’s greatest daily migration by hitchhiking through the deep on larger animals. Bioluminescent hunters communicate in flashes of living light, while strange creatures such as siphonophores challenge our understanding of what it means to be an individual animal. On the seafloor, ancient coral reefs thrive in darkness; methane seeps create unexpected oases of life.
Finally, aboard the legendary submersible Alvin, we descend to hydrothermal vents where towering chimneys fuel thriving communities that exist without sunlight, revealing a world that challenges one of our most fundamental assumptions about life on Earth.
With a raft of remarkable characters, discoveries, new technology, and the experiential testimony of deep-sea scientists, this film offers an entirely new perspective on the deep.
Reflecting on filming over 4 years and in over 37 countries, Executive Producer Elizabeth White said, “Anybody who’s ever SCUBA-dived will know that just being underwater can be a challenge in itself, let alone trying to film a tiny animal with a camera in a vast metal housing. Then there’s the habitat itself. Working underwater raises environmental issues to consider, like current, tides, temperature, visibility… everything is complicated! Then there’s the time you can spend underwater, which is often very limited. Even with the most advanced rebreather technology, divers have only a few hours underwater to get the footage we need before they have to return to the surface.
And then there are the really inaccessible ocean habitats – the vast open ocean, or the deep, where few humans go. Making those films took nerves of steel! The Open Ocean team could spend weeks just simply finding some of the animals they wanted to film (occasionally they didn’t!). The Deep team had to rely on relationships with scientists, piggybacking on cutting-edge science expeditions, often to places which have never been explored before. That was a completely different type of film to make, as the team could never be sure of exactly what they would get.
Underwater filming is definitely not for the logistically faint-hearted, but it’s enormously exciting!
The team we put together for this series are all underwater experts. For most of them, being underwater feels like second nature. That’s a great place to start. Pulling off a series like this has taken incredible dedication and passion, and I’m immensely proud of what the team has achieved.”
Episode Six: Future Seas
Our ocean is facing immense challenges, but for the first time, we have the knowledge and tools to help it recover. Future Seas follows the scientists, conservationists and communities working to secure a healthier future for the world’s oceans.
Overfishing remains one of the greatest threats to marine life, with illegal fishing placing growing pressure on vulnerable ecosystems. From shearwaters fitted with radar detectors to satellite surveillance backed by artificial intelligence, pioneering technologies are transforming our ability to track vessels, expose illegal activity and protect ocean wildlife.
Science is also revealing where conservation can have the greatest impact. The world’s largest tracking study of marine animals is identifying vital hotspots for feeding, breeding and migration, helping guide efforts to protect the ocean’s most important places. Globally, the landmark High Seas Treaty offers new hope for safeguarding vast areas of ocean beyond national borders.
In Indonesia, an ambitious breeding programme is helping bring the Indo-Pacific leopard shark back from the brink of extinction, raising vulnerable pups before releasing them into protected waters. Elsewhere, scientists are confronting threats that begin on land, from pollution to climate change, while searching for solutions that will protect marine life for generations to come.
Nowhere is the challenge more urgent than on the world’s coral reefs. On Australia’s Great Barrier Reef, a groundbreaking project is racing to preserve coral biodiversity, collecting and safeguarding species threatened by rapidly warming seas.
Filled with innovation, determination, and inspiring stories of recovery, Future Seas shows that while the challenges facing our ocean are profound, we have many of the tools needed to create an ocean healthier and richer than we have ever seen.
Blue Planet III premieres on November 1 on BBC One and iPlayer.
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