Mobile phone operator Meteor has said it now has a 16% slice of the market with 750,000 customers.
In November last year the company said customer numbers had topped 500,000.
Meteor CEO Robert Haulbrook said keeping your number, while switching network, was more important to bill pay and high use pre-pay customers.
The company said contract customers now make up almost 10% of customers, compared to 2% last year.
Meteor, which is owned by eircom, said it is planning a roll-out of new stores to bring the total to 40.