US Border Patrol Chief Patrol Agent Thomas G. Martin said the 13 migrants made landfall early Thursday morning near Big Pine Key, about 30 miles east of Key West.
Border Patrol agents along with deputies from the Monroe County Sheriff's Office responded to what they called a "maritime smuggling event" and took the migrants into federal custody.
The group made the journey from Cuba on a homemade wooden vessel, officials said.
The group was apprehended about a week after 16 Cuban migrants were taken into custody, also in the Keys, after arriving on a homemade raft.
Back in July, a group of Cuban migrants came ashore in Hallandale Beach and asked beachgoers for directions to Miami Beach.
In August, the U.S. Coast Guard in Miami said they rescued one Cuban refugee adrift off the coast. They believed three other migrants were dead after trying to reach land while using a makeshift raft.
"We cannot stress enough how dangerous it is to take to the seas and navigate the Florida Straits on unsafe vessels," Lt. Cmdr. Ben Tuxhorn, command center chief, Sector Miami, said in a statement.