Sudbury Post Office is to move to WHSmith in Market Hill.
The East Street store will close on November 9, with the new branch opening the following day.
The Post Office promises the new branch will continue to provide the same range of services but with longer opening hours, including Sundays.
Roger Gale, general manager for the Post Office’s Crown branch network said that the change would help to ensure the branch is commercially viable into the future.
“Our customers’ needs continue to change and we are responding to that, taking the right action to sustain our services for years to come,” said Mr Gale.
The move comes after a six-week public consultation.
The new branch will have four counters with opening hours from 9am-5.30pm Monday to Saturday and 10am-2pm on Sundays, nine-and-a-half hours more a week than currently.
A Post Office spokeswoman said existing branch staff had the right to transfer their employment to WHSmith in line with TUPE legislation and their options were being discussed with them individually.