iBasis Automatic Code Translator To Ensure Seamless International Phone Service As Mexico Transitions to New 10-Digit Dialing Format

New iBasis Network Technology Shields Carriers & Their Customers From Complex Code Transition, Helps Prevent Service Disruption, Revenue Loss on High-Volume Telecommunications Route

BURLINGTON, Mass.- October 1, 2001 - iBasis, Inc., (Nasdaq: IBAS), the leader in advanced Internet-based voice communications, today announced that it has developed an automatic code translator that it will use on its global VoIP network to help ensure seamless service to Mexico following the planned introduction of new Mexican city and regional dialing codes. Beginning November 17, 2001, Mexico is expected to move from 8 to 10-digit dialing for international calls to Mexico, concurrently reducing its number of city and region dialing prefixes from approximately 1400 to 406. The iBasis automatic code translator instantly maps all calls to the new, reorganized region and city codes, simplifying international service to Mexico, and enabling carriers to use The iBasis Network to route calls made using either the current 8-digit format or the new 10-digit format, indefinitely.

"Mexico has one of the most complex city and region dialing prefix systems in the world," said Ofer Gneezy, president and CEO of iBasis. "U.S. carriers, whose traffic helps make the U.S-Mexico route the second-largest telecom traffic route in the world, are scrambling to complete challenging code mapping projects in order to avoid the possibility of service interruption and consequent revenue reduction on this critical international route. After it is integrated with our Assured Quality Routing systems in early November, this new routing tool, developed by our expert network planners and engineers, is expected to enable us not only to continue to grow our traffic to Mexico, currently our highest volume destination, but, in addition, to help us ensure continuity of service to other countries that choose to revamp their code structures."

The iBasis Network in Latin America
Many of the world's largest carriers route international voice traffic over the iBasis Network, which has more than 581 points of presence in 70 countries, using its efficient global footprint to provide high quality international service. In Latin America, iBasis has relationships with more than 35 carriers in Argentina, Chile, and Mexico. These relationships helped iBasis grow its Latin American traffic by more than 246% and revenues by nearly 200% from Q2 2000 to Q2 2001.

iBasis guarantees its service quality, offering the industry's first Service Level Agreement (SLA) for VoIP (Voice-over-Internet-Protocol). The key to maintaining the high level of quality required by the world's largest carriers is the company's proven, proprietary Assured Quality RoutingTM (AQRTM) technology. At the company's 24 x 7 Network Operations Centers (NOC) in Burlington, Mass., USA and Hong Kong, the nerve centers of The iBasis Network, engineers continuously monitor the global circuit-switched (PSTN) and packet-switched (IP) networks to ensure the highest quality of service to customers worldwide.

About iBasis
Founded in 1996, iBasis (Nasdaq: IBAS) is the leader in advanced Internet-based voice communications. iBasis delivers toll quality international voice services and provides the infrastructure for hosted communications solutions, including unified communications and speech-enabled content, e-commerce and customer service applications. The company's customers include many of the largest enterprises and carriers in the world, including AT&T, Cable & Wireless, China Mobile, China Unicom, Concert, ExxonMobil, Gannett, H&R Block, Home Shopping Network, Morgan Stanley, NTT, Telstra, Sabre Group, Sprint, Western Union, WorldCom, and Verizon. iBasis' hosted, enhanced service solutions include SpeechPort^TM, a scalable, customizable ASP environment for speech-enabled business solutions, VoCore^SM messaging and the IP CallCardTM pre- and post-paid calling card platform. The iBasis Network is the world's largest international Cisco Powered Network for Internet Telephony and the first to receive the Unified Communications-Cisco Powered Network (UC-CPN) designation. iBasis is listed in both the Russell 2000® and Russell 3000® Indexes. The company can be reached at its worldwide headquarters in Burlington, Mass., USA at 781-505-7500 or on the Internet at www.ibasis.net .

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Except for historical information, all of the expectations, projections and assumptions contained in the foregoing press release, including those relating to the company's current expectations regarding revenue growth, sources of revenue, margin improvement and future capital expenditures constitute forward-looking statements under the Private Securities Litigation Reform Act of 1995 and involve risks and uncertainties. Important factors that could cause actual results to differ materially from such forward-looking statements include, but are not limited to, (i) the extent of adoption of the company's new voice-based Internet services and the timing and amount of revenue generated by these services; (ii) fluctuations in the market for and pricing of VoIP services; and (iii) the other considerations described as "Risk Factors" in iBasis' Annual Report on Form 10-K for its fiscal year ended December 31, 2000, and the company's other SEC filings.

Assured Quality Routing and AQR are registered trademarks, VoCore is a service mark and iBasis, The iBasis Network, Internet Central Office, Internet Branch Office, IP CallCard, SpeechPort, IPort, and PriceInteractive are trademarks of iBasis, Inc. or its subsidiaries. Cisco and Cisco Powered Network are registered trademarks of Cisco Systems, Inc. All other trademarks are the property of their respective owners.