<Page> EXHIBIT 23.2 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the use in this Amendment 1 to Registration Statement No. 333-117346 of iBasis, Inc. on Form S-1 of our report dated February 27, 2004 (which report expresses an unqualified opinion and includes an explanatory paragraph relating to a change in the method of accounting for goodwill and other intangible assets), appearing in the Prospectus, which is part of this Registration Statement. /s/ Deloitte & Touche LLP Boston, Massachusetts August 13, 2004