Using a novel exchange paradigm, we demonstrate that Australian preschool children from middle to high socioeconomic backgrounds may be capable of executing a mutually beneficial exchange. In Study 1, 3- to 5-year-old children completed a tower building task, in which they were given an opportunity to make trading choices via preset options that could allow both them and a puppet to succeed. A majority of children across age groups selected the efficient trade option over other alternatives. In Study 2, we modified the task to have less structure. With no preset options, 5-year-old children initiated an efficient exchange to a greater extent than younger children. A different task that relied on distributing desirable versus less desirable rewards (stickers) revealed a complementary pattern. The two studies shed light on the onset and developmental trajectory of a prerequisite skill for negotiation: children's capacity to initiate and execute a mutually beneficial deal, varying across different task contexts. (PsycInfo Database Record (c) 2024 APA, all rights reserved).