The carrier will offer a daily service from Heathrow to Sydney after flight BA15 landed at Sydney airport on Tuesday (29 March) at 6.21am.
To celebrate the milestone, BA’s customers in Australia are now eligible to join the Executive Club loyalty scheme.
Noella Ferns, British Airways’ head of sales, Asia Pacific, said: "British Airways has always had a strong link to Australia. For both business and leisure travellers, London is the major gateway for Europe and one of the most popular destinations for our customers down under."
Meanwhile, Geoff Culbert, chief executive of Sydney airport, said the cultural, business and family connections between Australia and the UK "run deep".
"It’s terrific to welcome British Airways back to Sydney airport as it resumes one of the most iconic routes in international aviation," he added.
