Abstract: Outside options can induce bargaining asymmetries that influence the outcome of international negotiations. This article focuses, however, on the impact of a regime-provided inside option on the willingness to cooperate and the distributive outcomes reached. Using a new data set covering 417 maritime boundaries, that fall under the Law of the Sea framework, this article shows that the ability to find agreement is closely linked to the distributional outcomes that states are able to realize. Different potential gains from cooperation result in bargaining asymmetries that influence both the ability to settle a maritime boundary and the distributive outcome reached when cooperation succeeds. Our evidence shows that the opportunity to invest in long-term projects that require legal certainty, such as offshore oil, facilitates cooperation and is associated with smaller distributional adjustments.