Shetland Islands Council’s internal ferries will begin running on a restricted timetable from Monday.
After consulting with with NHS Shetland, communities, key local services and businesses, the council designed new timetables.
Journeys will be run where they are deemed necessary for essential workers or to support businesses.
Each route has been looked at individually in order to take local needs into account.
Chairman of the council’s environment and transport committee, Ryan Thomson, said: “Government guidance is very clear on the need for as many people as possible to stay at home, but there are key workers as well as critical businesses and services who do need to use our ferries.
“We have known for some time that we would need to move to a basic timetable to make sure we could maintain the wider network, and we’ve been consulting widely to make sure this new system maintains and supports community resilience.”
Anyone who needs to use the ferries during travel restrictions must set up an account with the ferry service and afterwards bookings can be made online or by phone.
Serco NorthLink Ferries has also introduced a revised timetable aimed at providing a lifeline service between mainland Scotland and the Northern Isles.
The Aberdeen-Kirkwall-Lerwick service will operate on an off-peak timetable from Sunday.
One passenger ship will complete the Aberdeen to Lerwick route on Tuesdays, Thursdays and Sundays.
Lerwick to Aberdeen will be available on Mondays, Wednesdays and Fridays and Aberdeen to Kirkwall will operate on Thursday and Sunday.
A ferry will also leave Kirkwall for Aberdeen on Wednesday and Friday.
The revised timetable is expected to run until May 5 but could be extended further pending government advice.