This article focuses on the mentions that the documents of truce between Castilla and Granada (13th-15th century) establish about border trade. These had been already expressed in the Pact of Jaen in 1246, in which favourable circumstances for trade were established. Thus monarchs of both sides tried toobtain benefits from this economic activity that then had importance, as demonstrated through the dispositions that began to appear in the truces, which, over the time, will become more complex. Although most of these truces' dispositions give a broad treatment to the economic issues, giving greater freedom of trade and allowing the exchange of banned products, others establish a more restricted relation with the products. This study analyses the relevance of these entailments for the "border equilibrium" and, at the same time, how these allow to understand the border as a more open space that commonly has been assumed.