The Bristol International Balloon Fiesta, now in its 37th year, takes place at Ashton Court with more than 500,000 visitors expected.
Organiser Clive Bailey said Bristol was "the world capital for ballooning" and hosted Europe's "biggest free event".
The four-day festival starts on 6 August, with more than 100 hot air balloons expected to take part.
Dozens of hot-air balloons have taken to the skies over Bristol ahead of Europe's largest ballooning event.