The four-day Royal Welsh Show will be staged at Llanelwedd, Builth Wells, Powys, from July 20. The showground is adjacent to the A470 close to the junction with the A483.
Parking is free, but drivers without vehicle passes will be directed into the first available car park on the approach road used.
A fleet of shuttle buses will ferry people from outlying car parks.
Special trains will run from Swansea and Shrewsbury on the Heart of Wales line and passengers may alight at either Builth Road or Llandrindod Wells stations.
Adults paying on the gate will be charged £20 a head on the first three days and £18 on the fourth. Children aged 5 to 16 will pay £4 a day. Four day season tickets can be bought for £60 a person, while a season ticket for a family of two adults and three children costs £95.