The incident happened last week in Fort Wayne.
The boy's father said his son, Aziel, somehow got to the pool through an opening in a fence.
"I look out the kitchen doorway and see that the garage door was open, so I immediately ran out and started looking for him and couldn't find him," Alex Cavillo told WPTA-TV.
Officer Evan Myers saved the boy. He heard crying and found the boy floating on his back in the neighbor's pool.
Footage from his bodycam shows the officer pull the child out of the pool.
The family said they're extremely grateful for the help of Myers.
"I want to personally thank him deeply for being able to find my son," said the boy's mother, Savannah Ybarra.
The family says they plan to put up a fence of their own.