

	Communications Authority of Thailand Selects iBasis for Internet Telephony Thailand's International Carrier Joins iBasis Network™ to Help Meet Growing Demand For International Service Burlington, Mass.-February 24, 2000-iBasis, Inc., (Nasdaq: IBAS), the leader in international Internet telephony, today announced that the Communications Authority of Thailand (CAT), Thailand's international carrier, has agreed to route outbound international voice and fax calls over the iBasis Network™, the world's largest Cisco Powered Network™ for Internet telephony. Under the terms of the exclusive calling card licensing agreement with the Communications Authority of Thailand, iBasis' partner Hatari Technologies will route customers' voice and fax traffic over the iBasis Network™ to destinations around the world. "Our partnerships with China Unicom and other regional telcos in Asia are expanding the reach and increasing the efficiency of some of that region's most important carriers," said Craig Inouye, vice president, Asia Pacific region, iBasis, Inc. "Now, together with the expertise of our local partner Hatari, we are extending the benefits of Internet telephony to Thailand, another rapidly growing Asian market." iBasis Partners With Hatari Systems Hatari Technologies, iBasis' local partner, has played a key role in delivering this new Internet-based international service to The Communications Authority of Thailand. iBasis chose to partner with Hatari Technologies for their unparalleled market knowledge and country-specific technical expertise. Under this agreement, Hatari Technology will operate and maintain an iBasis Internet Branch Office that will be used to convert circuit-switched phone traffic from CAT customers into digital packets for routing over iBasis' global IP-based network. "Hatari is very excited to be working with iBasis, the leader in international Internet telephony, to help The Communications Authority of Thailand bring the benefits of Internet telephony to its customer base," said Wichai Wanavit, CEO of Hatari Technologies. "Together with CAT, we are uniquely qualified to lead Thai telecommunications into the future." The iBasis Network™ The iBasis Network™ is the world's largest international Cisco Powered Network™ (CPN) for Internet telephony. iBasis is the only Internet telephony carrier that guarantees service quality by 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 Routing™ (AQR™) technology. At the company's 24 x 7 Network Operations Center (NOC), the nerve center of the iBasis Network, located at iBasis' global headquarters in Burlington, Massachusetts, USA, engineers continuously monitor the global circuit-switched (PSTN) and packet-switched (IP) networks. Using the latest network management tools and iBasis' AQR technology, iBasis ensures the highest quality of service to customers worldwide. About CAT The Communications Authority of Thailand (CAT) is a governmental corporation responsible for the management and operation of postal and telecommunications services in Thailand. As the owner of Thailand's international gateway and other telecommunications infrastructure, CAT is investing in both submarine cable and a satellite network and is the provider of the upcoming intelligent network and ATM switching system. CAT ranks among the leading telecommunications service providers in the region. About iBasis Founded in 1996, iBasis (Nasdaq: IBAS) is the leader in advanced Internet-based communications. iBasis has built the world's first global IP network that delivers toll quality voice and fax service and other advanced hosted communications solutions, including VoCore, to global tier one carriers and other service providers. The iBasis Network™ is the world's largest international Cisco Powered Network for Internet Telephony. iBasis customers include 10 of the top 12 US international carriers. 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 Except for historical information, all of the expectations, projections and assumptions contained in the foregoing press release 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, the considerations described as "Risk Factors" in iBasis' preliminary prospectuses dated February 22, 2000, and the company's other SEC filings. ### iBasis, The iBasis Network and Assured Quality Routing are registered trademarks of iBasis, Inc. Cisco and Cisco Powered Network are registered trademarks of Cisco Systems, Inc.