Tiscali France Selects iBasis for International Internet Telephony

Leading Pan-European ISP Interconnects with The iBasis Network in France to Enhance International Service, Expand Global Reach

BURLINGTON, MA-May 21, 2002-iBasis, Inc. (Nasdaq: IBAS), the leader in Internet-based voice communications, today announced that Tiscali France, a wholly-owned subsidiary of Tiscali S.p.A, a leading pan-European carrier and ISP, has connected its voice service infrastructure with The iBasis Network. This interconnection enables Tiscali France to expand its global voice service footprint by routing international voice traffic over The iBasis Network - the global VoIP infrastructure for the world's largest carriers. The agreement also expands iBasis' footprint in France, Europe's third largest telecommunications market.

Tiscali France is an Internet communications company and an operator and distributor of value-added services to consumers and enterprises. Tiscali France combines the Liberty Surf Group, World Online France, None Networks (Freesbee), Infonie, Intercall and A Télécom into a single company, whose mission is to make the Internet a part of daily life by providing simple access and a vast array of innovative, personalized services.

"Tiscali is the second-largest ISP in France", said Rafi Kouyoumdjian, CEO of Tiscali France. "Connecting to The iBasis Network, the VoIP infrastructure for many of the world's largest carriers, will help us competitively improve our voice service and build on our popular, branded ISP service to grow our market in France".

"Our interconnection with Tiscali France represents a strong endorsement by one of Europe's pre-eminent competitive service providers," said Ofer Gneezy, president and CEO of iBasis. "Tiscali's strong presence in France, Europe's third largest telecommunications market, will help us continue to grow our business in Europe, which has quickly become our second-largest region for originating voice traffic."

iBasis in Europe
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. The iBasis Network carries millions of minutes of ordinary international phone traffic everyday to and from the region over the public Internet. According to industry analyst publication TeleGeography 2002, Europe has experienced the strongest international traffic growth of any region outside North America, and represented about 43% of all international traffic in 2000, (the latest year for which statistics are available).

Much of the growing demand for iBasis international VoIP services in Europe, as in other regions, has come from Tier 1 carriers, such as Tiscali. More than 60% of all voice traffic carried by The iBasis Network is generated by Tier 1 carriers, the world's largest and most demanding service providers.

About Tiscali
Tiscali S.p.A., (Nuovo Mercato, Milan: TIS, Nouveau Marché, Paris: 005773), is a European Internet company providing access, content and business applications, and other innovative communications services. As of 31 December 2001, Tiscali had 7.3 million active users and Internet traffic of 10.4 billion minutes. With 14.7 million unique visitors to the Tiscali portal in December 2001, Tiscali is confirmed as Europe's leading web property (Source: MMXI). Tiscali's corporate website can be found at www.tiscali.com

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 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, H&R Block, Home Shopping Network, Morgan Stanley, NTT, Qwest, Telefonica, Telenor, Telstra, Sabre Group, Sprint, Western Union, WorldCom, and Verizon. 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.