Port Arthur is located at 29°53'53" North, 93°55'42" West (29.898333, -93.928611).
According to the United States Census Bureau, the city has a total area of 143.76 mi2 (372.33 km2). 82.92 mi2 (214.76 km2) of it is land and 60.84 mi2 (157.57 km2) of it is covered by water. The total area is 42.32% water.
Port Arthur is located in the Central Standard Time (CST) timezone, GMT-06:00. It observes Daylight Saving Time (DST).