The settlers and explorers travelling to Australia would travel there through the Indian Ocean. So why were the first colonies established on the Eastcoast, and why has that never changed? The only bigger city on the western part of Australia is Perth, whereas the Eastern part has many bigger cities.
Hi, you'll find a few earlier answers here
Why was east coast Australia preferred to the west coast when originally colonized? featuring /u/yodatsracist
Why was the eastern coast of Australia more settled by Europeans instead of the closer western coast? featuring /u/Algernon_Asimov (follow his link for more)