The Ferry Footbridge, widely known as the Red Bridge, will be closed for maintenance next month but will remain red.
Work is planned to start on April 6 and last around a month.
The bridge can be retracted to allow ships to pass through to access industrial areas and this will continue during the work.
It will be closed for pedestrians, though.
A spokesman for West Sussex County Council said: “Shipping will still be able to pass through during the works.
“A free bus service, suitable for passengers with disabilities, will be provided for pedestrians.
“It will run every 30 minutes between 6am and 11pm.
“A timetable will be displayed at each end of the bridge, in Ferry Road and Wharf Road.”
The distinctive red structure will be painted using fluoropolymer paint.
According to the council, this should triple the refurbishment’s lifespan and reduce the bridge’s carbon footprint and future maintenance costs.
It will also contribute towards the county council’s aim of becoming carbon neutral by 2030.