Police, fire crews and a magistrates' court have moved into a new shared building in what is thought to be one of the first of its type in Wales.
The multi-million pound base in Llandrindod Wells is an attempt by the services to make savings.
Public bodies around Wales are looking at sharing office space to reduce costs in the wake of budget cuts.
In Wrexham, the fire and ambulance service are drawing up plans for a station they can share.
The new building in Llandrindod Wells has separate sections for Dyfed-Powys Police, Mid and West Wales Fire and Rescue Service and HM Courts and Tribunals Service.
There are also shared elements, including conference and lecture rooms, a dining area and a gymnasium.
Richard Davies, head of estates at Mid and West Wales Fire and Rescue Service, said reducing costs was one of the reasons why the three services had decided to share a building.
"We saw the benefits in sharing with other emergency services and hopefully there will be some savings made," he added.
'Fit for purpose'
The fire station has three double bays capable of holding up to six fire engines, and replaces Builth Wells as the new regional command centre.
Mr Davies said Llandrindod Wells was the first new station the mid and west Wales fire service had ever built. He said it had previously extended, refurbished or repaired existing stations.
Architects Lawray, who designed the entire building, said it had a number of green features, including low emission boilers and reduced water consumption, while power is generated via a combined heat and power unit.
It also has a grass-covered roof.
"We understand the building to be the first one of its kind within Wales, and sharing both land and resources seems to make perfect sense," said Chris Evans of Lawray in Cardiff.
An HM Courts and Tribunals Service spokesperson said: "The new, single hearing room, justice centre in Llandrindod Wells, which is part of a new multi-agency facility, will provide a modern, fit for purpose venue for court and tribunal hearings for the people of the town and surrounding area."
In other parts of Wales, Dyfed-Powys Police have been in talks to close a station in St Davids and move into the local fire station.
In north Wales, firefighters and police revealed last December they could move into shared purpose-built stations in Gwynedd.
North Wales Fire and Rescue Service and North Wales Police are planning to invest £800,000 in a new station in Nefyn.
Meanwhile, an IT hub for Torfaen and Monmouthshire councils and Gwent Police opened last year.