Tremors were felt across the Bristol Channel into England too.
Parts of Wales and England have felt the effects of a minor quake.
The quake, which measured 4.7 on the Richter scale, happened at 2:31pm around eight miles from Swansea in South Wales.
Seismologist Richard Luckett, of the British Geological Survey, said the quake was the largest in mainland United Kingdom since the 5.2 magnitude Market Rasen natural disaster in 2008, and was felt across a large area of Wales and England with the reports from Birmingham and Devon.
The British Geological Survey says a magnitude 4.4 quake has shaken southern Wales.
The epicentre of the natural disaster, North of Swansea.
Tina Anton wrote on Twitter: "Just had a tremor as in natural disaster in Cornwall!"
Roger Musson, from the BGS, said it was the largest natural disaster in Britain for the last 10 years.
Despite the lack of known injuries or damage, authorities said they are still seeing a high call volume as a result of the quake. The EMSC urged people not to call the emergency services simply to report the quake.