https://en.wikipedia.org/wiki/Western_Sydney_Airport -- it is expected to be open in December 2026, with an initial capacity of 5 million passengers, ramping up to 10 million passengers by 2031.

I will resolve this question based on any official statements from WSA around what actually transpired in 2027 (expected to be their first calendar year of operations). I will use whatever definition of "passenger" WSA uses.

Western Sydney Airport - Wikipedia