Iolo: Deifio yn y Barrier Reef

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.