The following is a summary of the different categories:
Category AM Mopeds/Light Quads < 50cc
Category A1 < 11 kW & 115cc < 125cc
Category A2 20 < 35 kW & > 245cc
Category A > 50 kW & > 595cc
(as of July 2022 - Representative vehicles for the Driving Test)
There are two ways to access what category of licence you wish to drive - Direct Access and Progressive Access.
You can get a Learner Permit to do the IBT in the below categories based solely on your age - this is known as Direct Access.
Category AM & A1 - 16 years
Category A2 - 18 years
Category A - 24 years
This access allows you to take advantage of your previous qualification in a lower motorcycle category - the advantage being that you can acquire a licence in a higher category by completing the appropriate IBT module - you do NOT have to take another driving test.
For example, having previously passed the Driving Test for Category A2 and held it for a period of 2 years you can now access the larger bikes in Category A ie. you do not have to wait until you are 24 years of age.
Remember! You can only use Progressive Access once.