Prices rose two per cent year-on-year to reach a new high of £191,006, however this was after recovering from a dip in the three months to the end of June.
Six local authorities established new peak prices in Q3 – Bridgend at £175,144, Carmarthenshire at £166,769, Cardiff at £239,788, Newport at £202,947, Pembrokeshire at £207,561, and the Vale of Glamorgan at £277,735.
Principality noted that house prices had risen particularly strongly in coastal areas associated with holiday homes and holiday lets.
For example, the annual growth rate in Pembrokeshire was 9.6 per cent, second highest in the country, while Conwy, with the coastal property hotspots of Abergele, Llandudno and Colwyn Bay had a growth rate of 7.1 per cent.
However, the average house price remains approximately 40 per cent lower than in England, where the average price is £305,000.
Perhaps more encouragingly, the number of transactions rose 5.6 per cent across the country.
Sales of terraced properties was up by 13.5 per cent over the year, followed by semi-detached properties up by 8.0 per cent.
Detached property sales numbers were largely unchanged, while flat transactions dropped 15 per cent.
Principality Building Society chief financial officer Tom Denman, said: “First time buyers, holiday lets and people seemingly not allowing the shadow of Brexit to deter them, means average house prices in Wales continue to buck the trend seen in regions across England.
“It also seems home movers are continuing to buy higher value properties and overall house sales are up compared to the same quarter in 2018.
“The growth in average house prices is underpinned by historically low interest rates, a shortage of housing supply and relatively high employment. It will be interesting to see if this upward trend continues for the rest of the year as Brexit negotiations reach a critical stage.”