West coast ferry operator Caledonian MacBryane (CalMac) has stopped taking new bookings on all of its services up to and including 15 July.
The company will also stop serving hot food on board its ferries to free up its staff to crew the vessels.
CalMac said it was currently able to operate to its normal timetabled service.
But it added that it needed to plan ahead for any impact the coronavirus may have on its operations.
CalMac said bookings that have already been made up to 15 July will be honoured where services were running.
People without bookings can turn up at a sailing and try to get on, but this would on a first come first served basis.
The firm said priority would continue to be given to emergency services and medical emergencies.
The company operates ferry routes in and to and from the Western Isles, including Ullapool to Stornoway sailings, and Inner Hebrides.
Managing director Robbie Drummond said: "The Covid-19 outbreak is creating an ever-changing landscape not just for CalMac but for all transport operators and indeed all businesses.
"Whilst we are currently able to continue operating our normal timetabled service, we have to plan for the impact of the virus on our staff at ports, on vessels and within our support services.
"It has been prudent, therefore, to pause our ability to offer customers advance bookings."