Sand City is located at 36°36'53" North, 121°51'0" West (36.614759, -121.850060).
According to the United States Census Bureau, the city has a total area of 2.93 mi2 (7.58 km2). 0.56 mi2 (1.46 km2) of it is land and 2.36 mi2 (6.12 km2) of it is covered by water. The total area is 80.75% water.
Sand City is located in the Pacific Standard Time (PST) timezone, GMT-08:00. It observes Daylight Saving Time (DST).