iBasis Announces Release Date For Second Quarter 2003 Results

BURLINGTON, MASS. - July 16, 2003 - iBasis, Inc. (OTCBB: IBAS), the leader in Internet-based voice communications, today announced that it will report second quarter 2003 financial results on Wednesday, August 6, 2003, before the opening of the stock market.

The company will also host a conference call to discuss the results of the quarter, led by Ofer Gneezy, iBasis president & CEO, on Wednesday, August 6, 2003, at 11:00 a.m. EDT. The public is invited to listen in by logging on at the company's website at www.ibasis.com.

About iBasis

Founded in 1996, iBasis (OTCBB: IBAS) is a leading provider of wholesale international telecommunications services. The company was named by service providers for two consecutive years as the best international wholesale carrier in Atlantic-ACM's annual International Wholesale Carrier Report Card¹. iBasis is a preferred provider for many of the largest carriers in the world, including AT&T, Cable & Wireless, China Mobile, China Unicom, Sprint, Telefonica, Telenor, Telstra, and MCI. iBasis has carried more than six billion minutes of international voice traffic over its global Cisco Powered NetworkTM, and is one of the ten largest carriers of international voice traffic in the world². Based on its revenue growth from 1997 through 2001, iBasis was ranked the #8 fastest-growing technology company in North America and the #1 fastest-growing technology company in New England in the Technology Fast 500 national program sponsored by Deloitte & Touche. The company can be reached at its worldwide headquarters in Burlington, Massachusetts, USA at 781-505-7500 or on the Internet at www.ibasis.com.

###

iBasis is a registered mark. The iBasis Network is a trademark of iBasis, Inc. Cisco and Cisco Powered Network are registered trademarks of Cisco Systems, Inc. All other trademarks are the property of their respective owners.