Fernando Tupa addresses the sometimes-overlooked yet fundamental principle that consent to international arbitration is forum-specific, and explores its significance and practical consequences for investment tribunals. The author proposes that, if there is only consent “in principle” to international arbitration by the host State in an investment agreement due to the lack of a forum (or the unavailability of the forum contemplated therein), a foreign investor would not be entitled to unilaterally initiate an investment claim against the host State under said agreement, absent a subsequent agreement between the foreign investor and the host State on an arbitral forum. He also draws some conclusions and warns against the dangerous consequences of ignoring this basic principle.