The new outlet is in a busy corner of St Peter Port in the Commercial Arcade.
The new Post Office replaces one that has been in the Tourist Information Centre for the past two years.
Number 7, which sits below the steps on the corner of the Arcade, was previously a post office before it became a pharmacy.
Guernsey Post's head of Corporate Engagement, Dawn Gallienne, says the location is important for footfall:
“We are really pleased to be opening our new Post Office right in the heart of town. Being part of the Arcade places us in a vibrant and well-used location, with convenient access for customers."
The building is listed but has a high front step. Dawn Gallienne says they are looking at altering this:
"We are working closely with the Planning Department and the State's Disability Officer to explore a long-term solution that will improve wheelchair access. In the meantime, we’re looking at options for a temporary ramp to better support customers with limited mobility."
Full postal facilities are available in the new outlet, including PO boxes.
A postal museum on the top floor will open at the end of July.
Number portability issue between Coop Mobile and JT resolved
Guernsey's emergency sleeping pods 'in demand'
Alderney one-step closer to getting a swimming pool
Tickets on sale for women's Muratti
Move to get a full size inflatable pool for Alderney
Three Guernsey seal pups released in spring sunshine
Work begins to clear fallen trees from Guernsey's Reservoir Walk
Guernsey Police to target drivers who put others in danger
