The Welsh education inspectorate, Estyn, said standards achieved by adults were "good or better" in 84 per cent of the classes it looked at, although it says too many students are failing to complete their courses in some colleges.
A similar all-in-one inspection regime will be created in England with the recently-announced plan to merge the Office for Standards in Education with the Adult Learning Inspectorate.
Susan Lewis, the chief inspector at Estyn, said: "We changed our inspection arrangements this year so that there is now a common approach to inspecting the education and training of learners of all ages."
Estyn's report went on to say that work-based training is still poor in the areas of health, public services, construction and planning.
John Graystone, chief executive of fforwm, the association of colleges in Wales, said: "One of the five colleges inspected by Estyn last year was deemed outstanding'in each and every programme area, so we are in a strong position to move forward with confidence." "We are pleased that the Welsh Assembly government has recognised that a huge proportion of Welsh school-leavers and adults have very low literacy and numeracy levels and that low basic skills clearly hamper progress to further education."