iBasis Announces Date For First Quarter 2008 Financial Results Release and Conference Call

BURLINGTON, Massachusetts – 04/14/2008 – iBasis (NASDAQ: IBAS), a KPN affiliate, today announced that it will report first quarter 2008 financial results on Monday, April 28, 2008, after the closing of the stock market. The Company will host a conference call that same day at 5:00 p.m. ET, led by Ofer Gneezy, its President and CEO.

The public is invited to listen to the simultaneous webcast by logging in through the iBasis investor relations website at http://investor.ibasis.com. The webcast is also being distributed through the Thomson StreetEvents Network to both institutional and individual investors. Individual investors can listen to the call at www.fulldisclosure.com, Thomson/CCBN’s individual investor portal, powered by StreetEvents. Institutional investors can access the call via Thomson’s password-protected event management site, StreetEvents (www.streetevents.com).

About iBasis

Founded in 1996, iBasis (NASDAQ: IBAS) is a leading wholesale carrier of international long distance telephone calls and a provider of retail prepaid calling services and enhanced services for mobile operators. iBasis customers include KPN, KPN Mobile, E-Plus, BASE, and many other large telecommunications carriers such as AT&T, Verizon, Vodafone, China Mobile, China Unicom, IDT, Qwest, Skype, Telecom Italia, Telefonica, and Yahoo. In October 2007, iBasis acquired KPN Global Carrier Services to create one of the three largest carriers of international voice traffic in the world, and KPN became a majority stockholder of iBasis. On a pro forma basis, the combined company carried approximately 24 billion minutes of international voice traffic in 2007. The Company can be reached at its worldwide headquarters in Burlington, Mass., USA at +1 781-505-7500 or on the Internet atwww.ibasis.com.