iBasis Supports Ten-Fold Growth of International Call Volume for Leading Provider in Greece

High Efficiency Interconnection to The iBasis Network Key Element in OTEnet's Expanding Global Service

BURLINGTON, MA - May 7, 2002 - iBasis, Inc., (Nasdaq: IBAS), the leader in advanced Internet-based voice communications, today announced that OTEnet, the leading ISP in Greece and subsidiary of OTE, (Hellenic Telecommunications Organization S.A.), is interconnected with iBasis for global Internet telephony. The relationship with iBasis, established in 2001 and announced today, has supported OTEnet's nearly ten-fold growth of its daily international call volumes since its launch.

OTEnet routes international voice traffic over The iBasis NetworkTM through an iBasis Internet Branch Office (IBO) facility, enabling an efficient, low cost, high quality IP-to-IP interconnection. iBasis is one of the world's 15 largest international carriers¹ and its network has more than 620 Points of Presence worldwide. An iBasis IBO comprises VoIP gateways and related interconnection equipment from Cisco Systems, which is deployed on the iBasis customer's premises.

"As Greece's leading Internet service provider, our success is driven by our ability to provide our customers with innovative, high quality services," said Panos Sarantopoulos, General Manager at OTEnet. "Interconnecting with iBasis for global voice service has played an important role in enabling us to grow our daily international call volumes nearly ten-fold over the past six months. With a direct IP connection to iBasis from our premises, we're able to take full advantage of Internet economics, and that makes it even more appealing."

"We are proud to help OTEnet quickly and cost-effectively deliver the benefits of carrier-grade VoIP service to its millions of customers across Greece," said Ofer Gneezy, president and CEO of iBasis. "Our interconnection with OTEnet expands our ability to carry voice traffic from Greece, which is not only home to the next Summer Olympiad, but is also one of Europe's most important trading centers."

iBasis in the Region
The relationship highlights iBasis' significant market presence in southeastern Europe - a region predicted to post four-fold growth in VoIP traffic by 2006². Through its carrier relationships, iBasis is able to provide service to several countries in the region including Bulgaria, Greece, Romania, and Slovenia. iBasis has led the move to VoIP in the region, growing its traffic to and from Southeastern Europe by 173 % from 2000 to 2001.

More than 44 European carriers are connected to iBasis for international service. These global carriers interconnect to The iBasis Network via the company's many Internet Branch Office facilities in the region, as well as at iBasis' larger, carrier-class Internet Central Office facilities in London, Paris, Frankfurt, and Amsterdam.

About OTEnet
OTEnet (www.otenet.gr) a subsidiary of OTE (Hellenic Telecommunications Organization S.A. - www.ote.gr), is the leading Greek provider of IP communications services to corporate and residential customers. OTEnet has evolved from being an Internet Provision company, to a company offering scalable network infrastructure and fully integrated IP-based telecom solutions as well as e-business and e- content services.

About iBasis
Founded in 1996, iBasis (Nasdaq: IBAS) is the leader in Internet-based voice communications. iBasis delivers toll quality international voice services and provides the infrastructure for hosted communications solutions, including speech-enabled content, e-commerce and customer service applications. The company's customers include many of the largest carriers and enterprises in the world, including AT&T, Cable & Wireless, China Mobile, China Unicom, ExxonMobil, Gannett, H&R Block, Home Shopping Network, Morgan Stanley, NTT, Qwest, Telefonica, Telenor, Telstra, Sabre Group, Sprint, Western Union, and WorldCom. iBasis' hosted, enhanced service solutions include SpeechPortTM, a scalable, customizable ASP environment for speech-enabled business solutions. The iBasis Network is the world's largest international Cisco Powered Network for Internet Telephony. iBasis is listed in both the Russell 2000® and Russell 3000® Indexes. 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 .

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Assured Quality Routing and iBasis are registered marks; The iBasis Network, Internet Central Office, Internet Branch Office, IP CallCard and SpeechPort 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.

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 services and the timing and amount of revenue generated by these services; (ii) fluctuations in the market for and pricing of these 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, 2001, and the company's other SEC filings. We have no current intention to update any forward-looking statements.

e no current intention to update any forward-looking statements.