Hampshire's Hythe Ferry was put in doubt earlier this month when its operator warned staff about possible redundancies.
It runs from Hythe, across Southampton Water, to the city's Town Quay.
About a 100 people staged a show of support earlier and more than 6,600 people have signed a petition calling for the service to be saved.
Councillor Malcolm Wade, of Hampshire County Council, previously described it as a "vital" service.
Peter King, from the action group that organised the demonstration, said it was an "essential and crucial transport link, and moreover a fundamental part of Hythe".
Hythe Ferry Ltd said it was holding talks with other operators.
It added it had suffered a "year-on-year decline" in passenger numbers and had also been met with higher operating costs.
Hampshire County Council said it had provided a subsidy towards the cost of operating the ferry for "a number of years".
"In principle, we would consider such an arrangement with any new operator," it added.
The issue is due to be discussed by Hythe and Dibden Parish Council on Wednesday.
One of the options being considered is a community group taking over the running of the pier, leaving Hythe Ferry Ltd to concentrate on the ferry service.
A campaign has been launched to save a "vital" ferry service which faces an uncertain future.