Seabrook is located at 29°33'48" North, 95°1'30" West (29.563611, -95.025000).
According to the United States Census Bureau, the city has a total area of 21.51 mi2 (55.71 km2). 5.73 mi2 (14.84 km2) of it is land and 15.78 mi2 (40.87 km2) of it is covered by water. The total area is 73.36% water.
Seabrook is located in the Central Standard Time (CST) timezone, GMT-06:00. It observes Daylight Saving Time (DST).