The line-up includes a choice of 1.2-litre TSI petrol (86bhp and 105bhp); 1.6-litre TDI diesel (90bhp and 105bhp); 1.8-litre TSI petrol (180bhp) and 2.0-litre TDI (150bhp and 184bhp) engines.
These engines boast low emissions and outstanding efficiency.
The model that is expected to be the volume seller, the 1.6 TDI, has emissions of just 99g/km, placing it in motor tax band A2. It can return fuel economy of just 3.8 l/100km.
The new Leon is all-new from the ground up and sits on the new Volkswagen Group MBQ platform and is five centimetres shorter than its predecessor, yet the wheelbase is up by almost six centimetres.
This results in a car with short overhangs, a spacious interior and, from the outside, a very purposeful stance.
Standard specification on all new Leon models is very generous and includes six Airbags (two front plus two side plus two curtain), air conditioning, a multifunction steering wheel and on board computer, the Media System Colour, with 5" Colour touch screen (MP3, USB/SD card/Bluetooth (phone & audio streaming)/CD / Aux-in, six speakers).
The all-new Leon starts from €18,995 for the 1.2 TSI Reference; €20,995 for the 1.6 TDI Reference 90bhp and €21,675 for the 1.6 TDI 105bhp.
The Style model starts from €21,395, with the FR specification starting from €26,825.
Speaking at the launch of new Leon to the Irish media, Cian O'Brien, Director SEAT Ireland, said: "The Leon is a hugely important car to us here in Ireland and it has proven to be very popular over the years with a variety of different customers.
"It is probably fair to say that it is the car that most people associate SEAT with here in Ireland. And this new model is truly outstanding."