Williamtown is a rural suburb of the Port Stephens local government area in the Hunter Region of New South Wales, Australia. It is located on the main road between Newcastle and Nelson Bay.

The eastern section of Williamtown is dominated by RAAF Base Williamtown and Newcastle Airport while the western section of the area is primarily semi-rural with some large-acreage residential areas scattered along Cabbage Tree Road which is a main access route to Port Stephens from the Pacific Highway. To the south Williamtown reaches Fullerton Cove, a large cove at the Hunter River. The south-eastern corner of the area reaches the Tasman Sea on Stockton Beach and access to the beach is possible at this point for off-road vehicles via Lavis Lane.

Williamtown possesses a humid subtropical climate (Köppen: Cfa), with very warm, wet summers and mild, relatively dry winters. Average maxima vary from 28.3 °C (82.9 °F) in January to 17.2 °C (63.0 °F) in July, while average minima fluctuate between 18.2 °C (64.8 °F) in January and February and 6.5 °C (43.7 °F) in July. Annual precipitation is moderately high (averaging 1,129.0 mm (44.45 in)), and is spread across 86.6 precipitation days (over 1.0 mm (0.039 in)). The town experiences 103.2 clear days and 127.3 cloudy days per annum. Extreme temperatures have ranged from 45.5 °C (113.9 °F) on 4 January 2017 and 11 February 2017 to −3.9 °C (25.0 °F) on 18 July 1970.

In the 2016 Census, there were 885 people in Williamtown. 70.9% of people were born in Australia and 80.7% of people spoke only English at home. The most common responses for religion was Anglican at 22.8%.

Most of Williamtown sits atop the Tomago sandbeds (an aquifer that is a critical source of water for the lower Hunter Region). The sandbeds are replenished primarily by rain as well as any water that leaks from Grahamstown Dam in nearby Ferodale. Water from the sandbeds and the dam is treated in Tomago.