iBasis Announces Successful Completion of $15 Million Stock Repurchase Program

BURLINGTON, Massachusetts – 08/20/2008 – iBasis, Inc. (NASDAQ: IBAS), a KPN affiliate, today announced that it has completed the repurchase of $15 million of its common stock, as authorized by its Board of Directors on April 28, 2008.

The company repurchased approximately 3.9 million shares at an average price per share of $3.84. With the completion of the share repurchase program, iBasis now has 71.2 common shares issued and outstanding.

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 more than 23 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.