Iolo: Deifio yn y Barrier Reef

Iolo Williams goes on a journey of discovery to find out about the health of wildlife in the waters of Australia's Great Barrier Reef. He begins his journey at the northern end of the reef, diving down to swim with huge barracudas and green turtles.

Iolo Williams dives down to the remains of the SS Yongala, a shipwreck that has been transformed into an artificial reef. He also discovers how mangroves help to protect the reef and meets Beth Ross from Blaenau Ffestiniog who has settled in Cairns, and talks about the importance of the reef to the local tourist industry.

Iolo Williams dives with sharks off Lizard Island, before travelling to Magnetic Island, where he meets wild koalas who have made the military forts their home.

Iolo Williams swims with sea snakes and moray eels at night, visits the most southerly part of the reef and dives through an underwater tunnel.