A green turtle approaches the camera, appearing curious about her reflection in its dome port. The photographer positioned the camera just below her eye level to create a more intimate portrait; staying within 3-10 metres of the surface kept the sunlight sharp, creating distinct rays through the water. A fast shutter speed and small aperture controlled the intense brightness, while a small amount of strobe light revealed the turtle’s details.

In the cold waters of Browning Pass, Canada, a giant Pacific octopus emerges from a reef covered in soft corals, sponges and clams. Its skin changes colour and pattern using specialised cells called chromatophores, which contain pigments. Tiny muscles also raise and flatten bumps called papillae, changing the skin’s texture to match its surroundings. These rapid changes help the octopus camouflage itself and can also confuse predators. The result is a remarkable display of colour, pattern and texture.

During a dusk dive in a Scottish sea loch, a torch reveals thousands of brittle stars covering the seabed. Their delicate arms form a striking pattern around a purple sea urchin. UK seas are cold, with strong tides and changing visibility, but their nutrient-rich waters support abundant marine life. Rocky reefs can be covered with kelp, anemones, sponges and soft corals, while fish, seals and sharks also visit.

An American crocodile moves through the mangroves of Cuba, a habitat that provides shelter for feeding, breeding, nesting and raising young. Beneath the trees, fallen leaves break down into nutrient-rich sediment. For the crocodile moving carefully is essential to avoid disturbing the soft mud and consequently reducing visibility. As the crocodile approached, the photographer remained still and captured it in its natural environment. The animal passed within touching distance before disappearing among the mangrove roots.

This tiny nudibranch – commonly known as sea-slug – was photographed in Queensland, Australia. Only about 1centimetre long, it is covered in delicate cerata, branching structures that help it absorb oxygen. Its vivid pink colour is an example of aposematism: bright colours and patterns that warn predators that an animal may be toxic or unpleasant to eat. Thousands of nudibranch species live in oceans worldwide, displaying an extraordinary variety of colours, shapes and adaptations.

In Western Australia’s Jurien Bay Marine Park, curious sea lion pups approached the photographer in the water. The playful animals chased, gently nipped and twisted around the camera, fascinated by their reflections in its curved dome port. They also appeared to copy the photographer’s movements, turning as she spun in the water. One pup even brought a starfish. This encounter reveals the intelligence, curiosity and playful behaviour of these young marine mammals.

A Caribbean reef shark swims through purple sea fans and porous sea rod in Jardines de la Reina, Cuba. The marine park has been protected since 1996, with limits on fishing and visitor numbers helping its reefs and wildlife thrive. Stretching for around 90 miles, the protected archipelago is known for healthy corals and abundant marine life. Caribbean reef sharks can reach three metres in length and are important apex predators, helping maintain balance within the reef ecosystem.

A male weedy seadragon carries hundreds of fertilised eggs on his tail in Tasmania’s coastal waters. Unlike seahorses, which carry eggs in a pouch, male weedy seadragons attach them directly to their tails, where they develop for around eight weeks. This species grows to about 45 centimetres long and is found only in Australia. Leaf-like appendages and detailed markings provide camouflage among seaweed and seagrass. A single brood can produce up to 250 hatchlings.

A mosshead warbonnet shelters inside a discarded glass bottle during a night dive in God’s Pocket Bay, Canada. These fish normally hide in rocky crevices, but the bottle’s narrow opening provides protection from predators. Some have been recorded living in bottles for up to a year. The bottles were once used by sailors and fishermen, who discarded them in the harbour during the 1800s. Today, they have become unexpected shelters for marine life.