Family name Ибай (Ibai 
, Ибай 
) , all over the world, is quite a rare cognomen. The cognomen Ибай is characteristic of Spain, where it is quite a rare surname, Japan, where it is a rare surname, and Kenya. Measured by absolute frequency, it is the most numerous in Japan, Spain, and India. Likewise, Ибай is the forename as well as the last name.