What is there to do and see on Kangaroo Island?

I've been to K.I about 20 times, and been on about 10 tours. The other day, I went on the Highlights Tour, which takes you to Seal Bay, which shows Australian Sealions in their natural habitat. Sometimes, the Sealions are about 20-30 metres away on the edge of the beach, but when I went this time they were within 7 or so metres. I got some really good pictures of sealion pups playing as well.

You then have lunch at the Vivonne Bay Outdoor Education Centre, which serves vegetarian meals as well as tasty salads, chicken and a chunky sausage. You can also buy some beer at their bar.

Next, you go for a Koala walk in Hanson Bay Sanctuary, which lets you see some koalas having their afternoon siesta.

After that, you drive through Flinders Chase National Park to Remarkable Rocks, which are very old, huge, sea sculpted rocks that you can explore and take pics of.

Next, you are driven down to Admiral's Arch, which hosts some NZ fur seals, also playing and sleeping, under a eerie arch by the sea.

All of this is run by SeaLink, and costs about $225 AU.
You can also do a number of other tours, by other companies and a few more by sealink.

Other cool places include:
Cliffords Honey Farm (really tasty honey icecream :P)
Emu Bay Eucalptus Distillery (they burn leaves, making them into ointments made of eucalptus oil)
Kingscote (good place to stay, luxury accom, pelican feeding, penguin tours, Island Beehive)
Penneshaw (another holiday house place, penguin tours, accom, fishing, swimming)
Emu Bay (beautiful beaches, fishing, holiday houses, swimming)
Little Sahara (sandboarding down sand dunes, HEAPS of fun)

So, go to sealink's website to book a tour or ferry ride.
Also, you can fly in with Regional Express (REX).

Kangaroos.

please go there if you enjoy natural habitat it is a must see. one of the most beautiful areas in sa. seal bay is a must. obviously there are also lots of kangaroos and koalas, there are some beautiful walking trails - take lots of photos!

Ive heard that the seals on the island are amazing and cute! Maybe do a google search of Kangaroo Island and see what comes up! Ive heard its nice.

Yes, I have been there 3 years ago. There is little Fairy Penguins, Koalas, Kangaroos, Echidnas, Possums, Seals on the beach. They have a lot of sight seeing too and trail walking. Beautiful night sky. You can also bring your car, which goes on the ferry. There is also the unique Ligurian bee colony. Because it so unique it is prohibited to bring honey to the island.
Below is a souce, hope this helps.

Have been lots of times but the best was when we took our mountain bicycles as a lot of the walking trails can be cycled on. We also cycled on the beach and picnicked at a light beacon and didn't see the sign on the gate---no entry ---as there is no fences on the beach (you cycle on the wet hard sand)
Going across in a yacht was a lot of fun although the crossing on the open ocean can be a bit rough but lots of easy fishing.

The spectacular coastline is made up of towering cliffs, beautiful sandy beaches, battered rocks and quiet secluded inlets. There are excellent diverse bush walking and fishing opportunities on Kangaroo Island.
Kangaroo Island incorporates typical farmland, remote national parks, bleak rocky cliffs, snug bays and sandy, un-spoilt beaches.
Kingscote, the largest town on the island is situated at Nepean Bay. Here you can watch pelican feeding at 5pm in the afternoon at the jetty, and see fairy penguins come ashore at night.
At the other end of the island, about 90 minutes by vehicle is the Flinders Chase National Park, where you may see kangaroos, koalas, wallabies, platypus and possums.
Seal Bay Conservation Park is a large sandy beach and dune area, where wild Australian sea lions rest after a day out at sea fishing. Here you can go on a guided tour onto the beach and see the Sea Lions in their natural beach habitat.
Other places of interest are: Remarkable Rocks, Little Sahara, Vivonne Bay and search for koalas at the Hanson Bay, visit Emu Ridge Eucalyptus Distillery & visit Cape Willoughby.