The full list of new opening times, which come into effect on Monday, November 28 2016, is available online at www.eastsussex.gov.uk/librarytimes or people can check them at their local library.
People can also use the online service at www.eastsussex.gov.uk/libraries 24 hours a day to access the e-library, renew and reserve books, update their details and download e-books, or use the automated renewals line on 0345 6080195.
A home library service staffed by volunteers is available for people unable to visit their library due to ill health, disability or caring responsibilities.
Cllr Chris Dowling, East Sussex County Council lead member for community services, said: “The changes are part of a wider libraries transformation programme aimed at ensuring the service meets changing demand and is sustainable in the future.
“The revised opening hours are designed to ensure libraries are open when people need them most, and as at present, times will still vary from place to place to reflect local need.”
Over 88 per cent of visits to East Sussex libraries take place between 10am and 5pm. The revised opening times will see a reduction in opening hours during less busy times.
All libraries will open on Saturdays and many will stay open until 6pm on Thursdays.
The changes were approved by East Sussex County Council earlier this year following a public consultation.