Runaway Bay is located at 33°10'22" North, 97°52'44" West (33.172921, -97.878916).
According to the United States Census Bureau, the city has a total area of 6.50 mi2 (16.84 km2). 2.31 mi2 (5.98 km2) of it is land and 4.19 mi2 (10.86 km2) of it is covered by water. The total area is 64.51% water.
Runaway Bay is located in the Central Standard Time (CST) timezone, GMT-06:00. It observes Daylight Saving Time (DST).