Guernsey Post has launched a consultation on the proposals, which could see 96 of the 141 roadside boxes shut, while three others could be moved.
Many of the boxes identified for closure now had an average of just five items or less a day.
Some are also in very close proximity, as the post box network has grown over more than 150 years.
‘We recognise that this proposal may be met with understandable reservations from some customers, and we want to assure everyone that this decision has not been taken lightly,’ said Guernsey Post chief executive Steve Sheridan.
The complete list of the boxes at risk will be released at the start of the consultation on 15 August, with landowners currently being contacted.
Currently there are six rounds to collect from all the boxes, which Mr Sheridan said was significant investment of resources.
Guernsey Post is currently carrying out an efficiency review, with the utility again looking at making voluntary redundancies, and Mr Sheridan said reducing the number of post boxes was one efficiency option being investigated.
He added that the number of letters had dropped by 60% over the last 10 years.
When it came to which post boxes would be kept, the company has prioritised retaining boxes in key community locations, such as near shops, banks and other public amenities to ensure continued accessibility for customers.
All boxes next to sub-post offices will also be kept, as will the oldest continually used post box in the world, which stands on Union Street in St Peter Port.
Mr Sheridan emphasised no final decisions had been taken yet on any box, but as islanders shifted how they use the postal service, changes were needed.
‘This proposed change reflects how people are using our services today and supports our goal of operating efficiently while maintaining accessible and reliable postal services,’ he said.
When it came to the consultation, the utility would not just be looking at whether there were many objections to a closure, but also about assessing how much a box was needed and used.
There are several options for the future of any removed or closed boxes. Some may be kept for when older boxes need to be replaced, while others may remain in situ if they were a local landmark.
Mr Sheridan noted that former post boxes also have a value, so some of might be sold.
Each post box identified for potential closure will soon carry a notice advising of the proposal and how to provide feedback.
Full details, including a list of affected boxes and an online feedback form, will be available at www.guernseypost.com from the start of the consultation.
The consultation will run between Friday 15 August and Friday 12 September.
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