International traffic climbed 1.9 per cent to 1.37 million passengers during the month, while domestic traffic was up 1.2 per cent to 2.3 million.
Arrivals from India recorded their second consecutive month of double-digit growth, up 11.2 per cent on September 2018 and up 8.4 per cent year to date.
Sydney Airport says a highlight for September was the air services agreement between Australia and Nepal, which aligns to the strong passenger growth the company has experienced in recent years.
Indonesian passenger growth was another highlight, posting 16.1 percent growth on September 2018.
Shares in Sydney Airport (ASX:SYD) are trading 0.36 per cent lower at $8.41.