The Castlebay-Oban route is one of four CalMac services to be updated.
Work is to be carried out at Oban Harbour as part of a planned maintenance programme.
Caledonian Maritime Assets Limited (CMAL) will replace the lifting cylinders on linkspan number two at Oban Harbour, with a planned start date of 23 January 2020.
The linkspan will be out of service for 10 days while work takes place.
During this time vessels will use the linkspan at berth number one, which was replaced earlier this year.
Minimal disruption to services is expected, as the work will coincide with the annual dry-docking of MV Isle of Lewis, which is the only vessel used for Oban Harbour which is unable to use Linkspan number one.
CalMac’s Director of Operations, Robert Morrison said: "We are pleased to say that we have been able to amend the timetable so that there is no reduction in overall sailings while this work is carried out.
"However, operating from one linkspan means that our turnaround for sailings is much tighter, so I would urge all passengers to pay particular attention to the vehicle and passenger check-in times for their sailing and to arrive in plenty of time. Once service changes are finalised these will be published on our website."
Ramsay Muirhead, Director of Port Infrastructure and Planning at CMAL said: “This project is part of our ongoing programme of harbour upgrades and modifications across our network to provide safe and efficient lifeline ferry services to communities around Scotland.
“We have worked closely with the contractor and CalMac to ensure there is as little disruption to services as possible while we replace the lifting cylinder at linkspan number two.
"Throughout the duration of the project, services will run from berth number one, however we would advise passengers to check CalMac’s website for any adjustments.”
The routes affected are:
Oban - Craignure
Oban - Coll/Tiree
Oban - Castlebay
Oban - Colonsay