Ugandan Ben Siwa won the men's race while Lenah Jerotich from Kenya won the women's title.
Cheering crowds lined the route, which went along Penarth, Cardiff Bay and Roath Park and finished outside the Temple of Peace in Cathays Park.
Organisers said more than £2.4m was expected to be raised for some 800 charities.
The race was the last in Cardiff before the city hosts the World Half Marathon Championships for the first time in March.
Nigel Roberts, chairman of organisers Run 4 Wales, said the event was bigger than before, which was "fantastic" ahead of the world championships.
"Today's route was lined with tens of thousands of supporters cheering on the athletes and we expect to double those numbers when the world's best come to Cardiff," he said.
"This event has grown and grown and I'd like to thank all the organisers, sponsors and volunteers for the hours of devotion they put in to making it not only Wales' biggest mass participation event but also one of Britain's top road running races.
"It never ceases to amaze me how many people are prepared to put in the training needed to run 13.1 miles but when you see the joy on their faces at the end and how much money so many of them raise for charity it is difficult not to feel inspired."
More than 22,000 runners have taken part in this year's Cardiff Half Marathon.