The company, which is Ireland's biggest operator of directory enquiries, was originally allocated 118899 as the code it would offer consumers in a number lottery operated by Oftel in May. However, its research has shown 118888 to be an easier number to remember.
The purchase comes amid preparations for a launch ad campaign by Partners BDDH, which saw off Leo Burnett in a two-way pitch for Conduit's creative account last year.
Unlike the three main competitors BT, Telegate and Infonxx, which operates under the brand name The Number, Conduit has yet to open its call centre for business.
It is not known how much Conduit paid for 118888. Infonxx paid little known start-up Leaf Telecom £2m for 118118 last autumn.
Separately, The Number has started its first advertising with a radio campaign by WCRS.