First responders were called to the home Sunday evening by two women, who were administering CPR when authorities arrived.
Fire rescue transported the kids to an area hospital where they died.
The children, ages 1, 4, and 6 years old, were playing outside, when an adult female watching them went inside to use the restroom, sheriff officials said.
When the woman returned, the children were gone, she told investigators.
The children had climbed inside a chest freezer, which was new to the property and was not yet plugged in or brought inside, authorities said.
The woman and another female at the home searched the property and the surrounding areas and eventually the freezer.
According to Suwanee County Sheriff Sam St. John, the two women, identified as the mother and the grandmother of the children, searched for up to 30 minutes and possibly as long as 45 minutes before finding the victims.
When they did locate them inside the freezer, they were not breathing. The women began resuscitative efforts and called 911.
"It is believed at this time, that when the children entered the freezer, and the lid closed, the hasp (lid fastener) fell shut, trapping the children inside. There was no padlock on the freezer,” according to a sheriff department news release.
Investigators said foul play is not suspected at this time, and St. John believes the deaths were a tragic accident, but the investigation is still ongoing.