The new centre opened on Wednesday at the Maldwyn Leisure Centre in Newtown.
Until yesterday health and care staff had been vaccinated at a smaller centre in Newtown, but working from the leisure centre will enable even more people to be vaccinated.
Powys Teaching Health Board said it was grateful for the support given by Freedom Leisure in helping get everything ready.
Hefina Anwyl from Staylittle was one of the hundreds of people over the age of 80 to receive their first jab.
She said: "There wasn’t a thing to it, didn’t feel a thing.
"It was well organised, staff were very friendly, just a shame we can’t have a cup of tea too!”
Dawn Robinson is a care worker and was also vaccinated. She said: "The arrival was well-organised and went very smooth.
"I have been reading a lot about vaccines and couldn’t help feel a little apprehensive, but the jab went absolutely fine, there was nothing to worry about.”
Every person over the age of 80 in Powys should now have had a letter inviting them for vaccination.
If you have not received a letter you can fill in a form at pthb.nhs.wales/coronavirus/covid-19-vaccination/over-80-in-powys-and-not-received-an-invitation-to-vaccination/.