From October 1, pay and display machines at Carmarthenshire County Council car parks will no longer accept the old £1 coins.
Signs are being placed on all machines to advise visitors of the change, which coincides with the end of the old £1 coin circulation.
The Royal Mint issued the new 12-sided coins in March, but council meters have continued to accept the old round edged coin since.
The council will be updating the cash boxes in its machines from the beginning of October.
Cllr Hazel Evans, executive board member for transport, said: “We’ve allowed a couple of months’ grace whilst the old £1 coins were still in circulation, but we now have to update our machines to only accept the new coins. We have already put up signs to advise drivers so we hope it won’t cause too much inconvenience from October.”
Income from the council’s pay and display car parks supports transport and parking schemes across the county.
However, the council provides over 15,000 free spaces per year as part of efforts to support town centre trade.
Town centre chambers of trade and business improvement teams across the county’s main towns can apply for the council to waive its parking fees up to five times a year as part of their campaigns and events.
Free parking is also offered at Llanelli’s Coleshill car park, close to the town centre, every weekend.