Two Welsh universities have declared themselves full a week before A-level results are announced and the annual clearing system gets underway.
Aberystwyth University and Trinity College Carmarthen say they will not enter clearing, which matches applicants with spare university places, this year for the first time.
The nine other Welsh universities say fewer clearing places will be on offer.
There will be reductions of up to two thirds in some.
Universities have been able to fill places early as applications have increased around 12% on average while the number of places has not risen in line with demand.
The assembly government has asked the body which funds universities, the Higher Education Funding Council for Wales, to make sure universities do not recruit above agreed numbers this summer, while a cap on university places will be introduced next year.
Clearing places at Swansea Metropolitan University will be down 67%, while 50% fewer will be on offer at the University of Wales Newport.
Bangor University said it would be targeting "high calibre students" hoping to study science, technology, engineering and mathematics subjects who obtain "very high grades".
Last year around 2,000 Welsh students earned their places at university through clearing, with approximately a quarter of those opting to study outside of Wales.
However, English universities are also reducing the number of places offered through clearing as the admissions process grows increasingly competitive following the introduction of a cap on student recruitment in 2009.
The number of students from England electing to study in Wales last year increased by 14%.
A Welsh Assembly Government spokesperson said: "There has been a steady growth in the number of students going into higher education.
"Application to university has always been a competitive process and we are aware that a number of institutions are not using clearing this year.
"Sadly, every year some good applicants are disappointed.
"Applicants should also consider the higher education opportunities available in further education colleges which offer foundation degrees as well as part-time programmes which have close links with employers and allow opportunities for work placement."