Watch Coast Season 3 in Australia

Over 230 islands make up the Northern Isles - The Shetland and Orkney. These magnificent islands are made up of rock stacks, secret inlets and spectacular scenery, surrounded by sometimes extreme sea and weather conditions that have shaped these islands. Neil Oliver joins an expedition climbing the Old Man of Hoy in Orkney and finds out about the Second World War freedom fighters who risked their lives running the "Shetland Bus". Miranda Krestovnikoff goes in search of an elusive octopus, Nicholas Crane finds evidence of a tsunami that devastated Britain 7,000 years ago and Alice Roberts unearths a mysterious skeleton that reveals more about the lives of ancient Shetlanders.

Neil explores why Sandbanks in Poole Harbour has some of the world's most expensive houses. Alice builds her own coastal 'property' as she investigates the perfect sandcastle. Dick joins an American serviceman on an emotional journey, as he returns to the beach where he was given up for dead during World War Two.

Miranda is in search of the biggest sharks in British waters. Mark sees the Royal Navy's next generation of top secret 'Attack' nuclear submarines and Alice meets a woman who as a child was in the Isle of Man's internment camps, where 'enemy aliens' in Britain were held during the Second World War.

Neil discovers how a beach became the 'fastest place on earth' 80 years ago. Mark explores how Swansea's monopoly of the copper trade sped Nelson towards his Trafalgar victory. Miranda joins dolphins at the coast raising their young and Alice boards a dredger to discover how much sand we are consuming.

Miranda dives into a marine reserve off St Abbs, one of Britain's sites for underwater wildlife. Neil recreates a wartime scheme to train seagulls to search for German U-boats and Hermione explores the 400-year-old connection between a picturesque village and the birth of deep coal mining in Britain.

Neil discovers how mysterious flotsam inspired Columbus' journey to America. Alice explores the botanical puzzle of "The Burren" - where Arctic plants grow next to Mediterranean flowers. Miranda reveals the surprising secrets of seaweed that make it the special ingredient in everything from toothpaste to beer.

Neil explores the site of an experimental Radar, built to spy on the Soviet Union. Alice tries to capture the beauty of Southwold in paint. Nicholas discovers how tides and weather can cause catastrophic floods and Hermione meets a woman who intercepted German radio messages from the Norfolk coast during World War 2.

Neil investigates the tragic story of the first channel swimmer. Alice explores Jersey's remarkable post war transformation from Nazi stronghold to 'Honeymoon Island'. Miranda enters secret caves and Mark reveals why the islanders on Guernsey remain loyal to the Queen, despite being outside the United Kingdom.