Transport Minister Oleg Butkovic, the town's former mayor, was among the revellers. He said in his address to the press that 2019 was a good year for the national economy, especially tourism.
Revellers were served with spicy mulled wine and goulash.
Similar open-air parties were also held at noon in Fuzine, inland from Rijeka, and other towns to see off the outgoing year. Some of the parties were organised for children.
New Year's Eve outdoor parties will be organised in main squares of many Croatian cities.
In Osijek, several men traditionally dived into the waters of the Drava River at noon of 31 December.