The BBC has reported about 2.2 million fewer single-use cups were used by public bodies in Wales in the last year. This is a drop of nearly 19 per cent.
According to the BBC, hospitals, emergency services, councils and government organisations have said they are trying to reduce the amount of waste produced by the cups.
Eight out of the 43 bodies asked said they did not buy single-use cups in 2018-19, and seven of those have also withdrawn plastic straws and cutlery.
BBC Wales following a Freedom of Information request were given the results, which also showed a £71,000 fall in the amount spent on single-use cups between 2017-18 and 2018-19.
Rebecca Colley-Jones, a trustee of the Chartered Institute of Waste Management, said: "Two million is a big decrease. It's very positive. These things don't happen overnight. You take it a step at a time."
She said single-use plastics were a convenience for most, but added: "Perhaps what's happened over the last year or so is that people realise the consequences of it.
"Everyone will now have been getting used to a little inconvenience."
Cardiff University has gone plastic-free. A spokesman told the BBC: "The phasing out of single-use plastics across the university is one of a number of measures that we've put in place to help build an inclusive, sustainable and resilient future for our community and to bring about environmental benefits not only to Cardiff and Wales but to the wider world."
"We are extremely pleased with the progress we've made over the past year, however we are not complacent and will continue to look at ways in which we can reduce our campus footprint."
Since 2018-19, Monmouthshire council said it had stopped using plastics, while others are investing in biodegradable cups or encouraging staff to have re-useable cups and plastics.
Bettina Gilbert, programme manager at charity Wrap Cymru, said: "It's great news that Wales' public bodies are reducing the number of single-use plastic cups they're using and tackling 'problem plastics' such as straws and plastic cutlery, to be eliminated by the end of 2020 under WRAP's UK Plastics Pact. But these figures show there's still work to be done.”