The High Street property in St Davids is being sold with the limited company that has operated it since 1975.
The 17 apartments contain 36 bedrooms: 10 have two bedrooms, two have three and five have one.
The apartments surround a central courtyard with communal seating, while some have private balconies overlooking the courtyard or city centre.
Most apartments have gas central heating; two have electric heating.
The property has a communal entrance with intercom access, a private car park and extra spaces across the road.
It also has a reception area, laundry room and storage room.
Its layout and central location offer investment potential, including residential lettings, private tenancies or holiday accommodation, subject to the necessary consents.
The property is within walking distance of St Davids Cathedral and local amenities, with Pembrokeshire Coast National Park beaches and coastal walks nearby.
West Wales Properties, which is handling the sale, said the property had “huge income potential” and was “realistically priced”.
The company also called it a “fantastic investment and income opportunity” with a potential yield of 14 per cent.
The freehold property has mains drainage, electricity, water and gas.
The council tax band has not yet been confirmed.
The ground-floor commercial units are not included in the sale.
West Wales Properties said the building had “never been on the market” before.
It is on the market for offers over £3 million.
Viewings are by appointment.
West Wales Properties said: “A rare opportunity to acquire St Davids Apartments Ltd, together with an impressive residential building occupying a prominent position on the High Street in the heart of Britain’s smallest city.
“Ideally situated within walking distance of the iconic St David’s Cathedral and an excellent selection of local amenities, this substantial property presents an exciting and versatile investment opportunity.
“A substantial residential accommodation and a wealth of potential opportunities, this is a unique proposition for investors seeking a significant property asset in one of Pembrokeshire’s most desirable and historic destinations.”
