Which branch of the military does the Coast Guard operate under during peacetime?

The Coast Guard operates under the Department of Homeland Security during peacetime. This structure was established to allow the Coast Guard to focus on its missions related to maritime safety, security, and environmental stewardship within the United States. By being part of the Department of Homeland Security, the Coast Guard plays a critical role in protecting U.S. borders against threats, including drug smuggling and illegal immigration, as well as responding to natural disasters and maintaining maritime security.

In times of war or during specific situations, the Coast Guard can be transferred to the Department of the Navy, where it operates under naval command. However, in normal peacetime operations, its alignment with the Department of Homeland Security emphasizes its law enforcement, search and rescue, and humanitarian missions.