Scholars increasingly acknowledge that international institutions interact with each other, especially across issue areas such as trade and environment. However, scholars continue to dispute whether, and under what conditions, such regime interplay has positive or negative impacts on the effectiveness of international institutions. Existing scholarship debates whether international regimes may be compromised by inconsistencies, or whether enhanced reputational benefits make governments more likely to uphold commitments across components of a regime complex. This article examines how institutional complexity affects state behavior. Specifically, it analyzes how governments respond to regime inconsistency, and whether they continue adhering to their commitments in the absence of material or sociological non-compliance costs. The study tracks how state preferences and behavior changed over time when exposed to inconsistent international legal commitments regarding trade and regulatory rights in the South Pacific swordfish fishery. In this case, both World Trade Organization and United Nations Convention on the Law of the Sea rules were at stake, and both dispute settlement forums accepted jurisdiction over the case. Nonetheless, Chile and the European Community resorted to negotiation outside of — but still bounded by — these established rules. Thus, this study finds that when multiple regimes regulate a particular situation, bargaining continues to take place within the boundaries established by those rules.