Police are working to see if the robberies are related, said Capt. Mark Bollinger, spokesman for the Rock Hill Police Department.
In all three robberies, the gunman wore a mask, police reports show.
The latest incident happened around 12:40 a.m. Tuesday at the Hampton Inn on Tabor Drive, off Dave Lyle Boulevard near Interstate 77 Exit 79, police said.
The motel employee told officers a man wearing a black mask, a hoodie and carrying a handgun walked into the lobby and demanded money, according to an incident report. The employee handed over cash from the register and the man fled on foot, police said.
A K-9 team and more officers tried to track the suspect, but no arrests were made.
Police have video surveillance, but have not released the video.
On April 4, the clerk and a guest at the Courtyard by Marriott on River Run Court were robbed by a masked man with a gun, police reports show.
On March 22, the clerk at Baymont Inn & Suites on Anderson Road was robbed by a masked gunman who told the clerk he would shoot her if she did not hand over the money, a police report showed.
Andrew Dys: 803-329-4065, @AndrewDysHerald