Tri-Rail (reporting mark TRCX) is a commuter rail line linking Miami, Fort Lauderdale, and West Palm Beach, Florida, United States. It is run by the South Florida Regional Transportation Authority (SFRTA). The 70.9-mile-long (114.1 km) system has 18 stations along the South Florida coast. The system connects directly to Amtrak at numerous stations, and the Metrorail in Hialeah (Miami) at the Tri-Rail and Metrorail Transfer Station. In 2012, it will connect with both systems at Miami Central Station at Miami International Airport. A second Tri-Rail line on the Florida East Coast Railway corridor may be in operation by 2014, eventually extending service north to Jupiter, Florida and south to Downtown Miami, as well as numerous intermediate cities such as Hollywood, and inner city Miami neighborhoods such as the Design District, Little Haiti, and Wynwood.

Planning for the system began in 1983, and building the organization began in 1986. The current system was formed by the Florida Department of Transportation and began operation in 1989, originally to provide temporary commuter rail service while construction crews widened Interstate 95 and the parallel Florida's Turnpike. Tri-Rail was free from opening until May 1, 1990, at which time the fare was four dollars round trip. Due to higher than expected ridership, Tri-Rail outlasted its temporary status, adding more trains and stations in the process. Line extensions have enabled Tri-Rail to service all three South Florida international airports: Miami International Airport, Fort Lauderdale – Hollywood International Airport, and Palm Beach International Airport. The state's original plan was to use the more urban Florida East Coast Railway (FEC) line, but FEC declined the offer as they wanted freight to be their top priority.