Several roads in Cardiff were closed for the 10k race at Cardiff Bay.
More than 6,000 runners were expected for the Brecon Carreg Cardiff Bay Run. A 2k family run started at 10:00 BST followed by the 10k (six mile) run at 11:00.
Lloyd George Avenue, Pierhead Street and Central Link road was shut between 10:00 and 13:30.
Organisers asked competitors to consider using public transport, walking or cycling.
The regular Sunday rail service from Cardiff Queen Street Station to Cardiff Bay station will be in service as well as bus routes.
🏃♀️WE HAVE LIFTOFF!🏃♂️ pic.twitter.com/c6IzsPTeqG— Cardiff Bay Run (@CardiffBayRun) March 25, 2018