“We really do advocate wearing masks,” said Head of the Civil Contingencies Authority, Deputy Peter Ferbrache.
“It’s not being made compulsory at the moment, but it’s strong, strong advice, that people wear masks.”

Pictured: Efforts have been focused on getting the public to wear masks, and wear them properly.
The use of masks is intended to mainly protect others, not the user. It covers the mouth and nose, both of which are the main confirmed sources of transmission between people.
Guidelines have been published on the States of Guernsey website:

A number of questions have arisen from the push for masks this time around, and CCA Advisor Deputy Heidi Soulsby has suggested we follow common sense, and respect each other when out and about.
Just use common sense. It’s all about preventing spread of infection. So no, if there’s no one around you mask isn’t necessary obv, but if you’re walking and come across others who are, mask up, cover up and/or keep your distance. Indoor public areas you really should.
— Heidi Soulsby (@HeidiSoulsby) January 24, 2021