Eir's SIM-only mobile service GoMo has increased its 'for life' offer from €12.99 a month to €14.99 a month for new customers.
When it first launched, GoMo's offer started at €9.99 and then increased to €12.99.
GoMo has more than 250,000 customers and these customers will see no price change.
The no-frills service offers a SIM-only option and with no shops or other physical presence, it offers its customer services over the internet.
SIMs are sent by courier to the address of the customer.
GoMo uses Eir's network and offers 99% population coverage.
GoMo also said today that it is introducing 4G Calling and WiFi Calling for all customers on the new €14.99 offer, adding that it plans to roll out 4G Calling and WiFi calling to all existing customers by the end of the summer.
Caroline Lynch, GoMo Marketing Lead, said that 4G Calling means a faster call connection - twice the speed of 3G calls - as well as improved call quality for its customers.
"A major benefit for new GoMo customers is that 4G Calling makes multitasking possible, so during a call users can send emails, browse social media and watch videos, without disruption, using their mobile data," Ms Lynch said.
"In addition to this, WiFi Calling allows customers to use their mobile phone through any WiFi Connection, this will improve their indoor coverage and allow them to make calls and send texts anywhere in the world for the same price as at home, on WiFi Calling enabled devices," she added.