People visiting Yr Wyddfa— the country's tallest mountain— will now be required to book a parking space 24 hours in advance of their arrival.
When restrictions were eased last summer, as many as 500 cars were parked along the roads leading up the summit.
The pre-booking system will be in place in Pen-y-pas— the starting point for many of the most popular paths up Yr Wyddfa.
Parking tariffs start from £18 for between one and eight hours.
12 hours will cost £25, while 24 hour-parking will cost £40.