Japanese internet security firm Trend, which is based in Cork, is to recruit 100 people over the next three years in an expansion of its Irish operation.
Meanwhile Gala, which specialises in online games and is also headquartered in Japan, is to expand its European headquarters in Dublin's Digital Hub, adding 50 jobs.
The 150 new jobs are being supported by IDA Ireland and were announced to coincide with the Taoiseach-led Irish trade mission to Japan.
Another three investments involving Japanese companies have also been announced in the area of research and development.
Alps is to set up a project to design new car safety technology for the European market, while Shimadzu is collaborating with The Applied Optics Group in NUIG Galway in the area of imaging techniques.
Meanwhile, Sony and Toshiba - as well as US giant IBM - will be involved in a research centre on the Cell Broadband Engine, the computer chip which powers Sony's Playstation 3 and some of Toshiba's laptops.
Trinity College has been chosen as the centre's location.