The humpback whale migration passing Sydney takes place between April and December each year. The season is split into two distinct sections depending on the direction of travel of the majority of whales at that time.
The migrating population is named the Group 5 Southern Hemisphere humpback whale population or the Australian East coast humpbacks. As distinct from other humpback migration populations that travel along the West Australian and South African coasts.
The distance from the coast of the whales is believed to be based on the movements of the ocean currents, primarily the East Australian Current. The East Australian Current is a strong southerly current that the humpback whales make use of during their southern migration. On the Northern migration the Humpback whales will often use the Inshore Northern current, which is a north flowing counter current to the EAC. The main purpose of the annual humpback migration is to breed.
There are many companies that offer Whale Watching expeditions from Sydney Harbour,