iBasis Announces Redemption of its 6¾% Convertible Subordinated Notes 
  Burlington — August 16, 2005 — iBasis, Inc., a leader in international long distance, VoIP, and prepaid calling cards, announced today it will redeem all of its outstanding 6¾% Convertible Subordinated Notes due June 2009. The redemption date will be September 6, 2005. The aggregate principal amount of Notes outstanding is $32,599,000. 
  The redemption price will be $1,000.00 plus accrued interest up to but not including the redemption date for each $1,000.00 Note principal amount. The redemption of the Notes will be funded from existing cash, cash equivalents and short-term marketable investments. Holders of the Notes will be notified by the Trustee, The Bank of New York, of specific instructions regarding redemption of the Notes. 
  Holders have the right to convert their Notes into iBasis Common Stock at any time before the close of business on September 2, 2005, the business day immediately prior to the redemption date. The Notes are convertible into Common Stock at a conversion price of $1.85 per share. The Company will pay cash in lieu of fractional shares upon conversion of the Notes. No accrued interest will be paid upon conversion of the Notes.  |