At sunset, a big old kangaroo appears near the lighthouse, his muscular frame an impressive picture of strength. But when British navigator Matthew Flinders named Kangaroo Island in 1802, he did not do so as an eco-tourist - rather as someone rejoicing at finding a supply of fresh meat.

At Seal Bay, westwards along the southern coast from Cape Willoughby, park rangers lead tours of the sea lion colony on the beach, a highlight of any visit. Large bulls survey the crowd warily as they slide down the sand towards the shoreline, while mothers, known as cows, rest after fishing trips and their pups frolic in the shallows.

The next lighthouse sits at the island's southwest tip: Cape du Couedic. Made from beige-coloured local sandstone with a red-painted top, the tower was completed in 1909 and is the most beautiful on the island, though whether that provided consolation for keepers and their families in a spot so isolated it was originally inaccessible by land is doubtful.

The silence once day-trippers have departed is wonderful. It's easy to slip back in time in the lounge room of Karatta Lodge, one of three solid sandstone cottages with slate roofs built for the lighthouse-keepers, with its comfortable armchairs and antique furniture. There's no television, no mobile phone reception and no need for the laptop.

According to a book written by the son of an assistant keeper in 1933, life back then was a challenge. The automation of the lighthouse in 1957 brought to an end an era of encounters with snakes, doctor's instructions relayed by phone from Rocky River on the mainland and stuffing newspaper into gaps in the skirting board to keep the wind out.

Boardwalks lead to viewing points on the coast, where you can watch waves crash relentlessly onto the Casuarina Islets, also known as The Brothers, driven by westerly winds from the Great Australian Bight. Through the flying spray, seals make their way onto rocks from raging seas. At Admirals Arch, a natural rock formation buffeted by Southern Ocean waves, New Zealand fur seals relax and play - but the stench is shocking.

Other spots worth a visit at the southern tip of Kangaroo Island include the Remarkable Rocks, sandstone boulders eroded into unusual shapes by the elements, and the Kelly Hill Caves, with their stalagmites, stalactites and the rarer hook-like helictites: crazily curved mineral growths.

For lunch, head to the centre of the island, up Harriet Road, a winding dirt path that seems to lead to the middle of nowhere. Luckily Marron Cafe is marked on the tourist map. The restaurant serves delicious dishes based on farmed marron (the local crayfish) accompanied by excellent chardonnay from its vineyard, Two Wheeler Creek Wines.

Further north, Harriet meets the Playford Highway, an ironic title for a road that metamorphoses into an unsealed track.

Being perched on a cliff there was no need for height, so the government of 1858 built the lighthouse at Cape Borda short and square, the cheapest option. Displaying some rivalry, its guide describes this as the only square stone lighthouse in South Australia. It has one small red cannon, which, amazingly, was considered a deterrent against the Russian naval threats of the 1800s. The gun is fired daily at 1pm.

Flinders Light Lodge, an assistant keeper's cottage built in 1937, provides visitors with the opportunity to see what dusk brings. First a grey kangaroo and her joey appear in search of food, and then finally one of the less common and much smaller Tammar wallabies is spotted in the dwindling light.

In the morning, a stop at the Harvey's Return cemetery provides a harsh reminder of the isolation experienced by those who kept the ships safe. Sixteen members of lighthouse-keepers' families are buried here, including the first keeper, Captain Woodward.