O ddydd Sul 31 Hydref ymlaen bydd pob oedolyn yng Nghymru sydd wedi cwblhau eu cwrs dau ddos o'r brechlyn COVID-19 a'r rhan fwyaf o blant a phobl ifanc dan 18 oed, sydd wedi teithio o wledydd nad ydynt ar y rhestr goch, yn gallu cymryd prawf llif unffordd ar ddiwrnod 2, neu cyn hynny, ar ôl iddynt gyrraedd y DU.
From Sunday 31 October all adults in Wales, who have completed their two-dose course of the Covid-19 vaccine and the majority of under 18s, who have travelled from countries which are not on the red list, will be able to take a lateral flow test, on or before day two of their arrival into the UK.