The Great Ocean Road, located in Victoria, is arguably one of the best scenic drives of the world. Its official length is 243 kms (approximately 150 miles), but it will take you a full day to enjoy it due to the narrow and windy traffic lanes (only one in each direction). It hugs the coast line with panoramic views of the ocean and cliffs, and it winds its way through cool climate rain forests.
There are many beaches that you can stop and swim at along the drive, and also numerous townships, hikes, and other attractions for you to partake in.