The ferries which cross the River Murray at Tailem Bend, Wellington and Narrung will each be closed for several hours this week, the Department of Planning, Transport and Infrastructure has advised.
The closures will be necessary so routine maintenance work can be carried out.
The Wellington ferry will be closed on Tuesday between 10am and 2pm.
The nearest alternative crossing will be at Tailem Bend.
The Narrung ferry will be shut between 9.30 and 11.30am on Wednesday.
Anyone who must make the journey during those hours will have to go via Meningie.
The Tailem Bend-Jervois ferry will close between 1pm and 3pm on Thursday.
Alternative crossings in that case will be the Swanport Bridge and Wellington ferry.
The department thanked motorists for their patience.
The Tailem Bend ferry service was closed for two days just three months ago when the old wooden-hulled vessel was replaced with a new steel-hulled one.