<p>Geoconservation aims to protect the legacy of the Earth, and an integral component is decision-making. Decisions in geoconservation impact residents and other stakeholders; therefore, strategies to facilitate participatory decision-making are needed. Here, we present a strategy to facilitate the implementation of the Analytic Hierarchy Process (AHP) with a diverse group of stakeholders in Portland, Jamaica, without previous experience in the mathematical model. The AHP uses pairwise comparison matrices to assign numerical values to different components of a decision model, representing preferences in given scenarios. We designed a participatory session that guided workshop participants through the implementation of the AHP to decide between two hypothetical proposals for geoconservation in Portland, community-based tourism versus a resort, incorporating two criteria in the model: funding and reef health. We facilitated a session in which each community member (n = 20) had a voice in the decision process. Our results show that local stakeholders defended community tourism as viable and desirable to protect the land–ocean system in connection to people in east Portland (i.e., community-tourism was 73.6% preferred over resort). When only considering funding available to execute the project, the resort appeared to be the preferred option (i.e., 75.0% preferred over community-based tourism); however, when only considering reef health, most participants stated that community tourism would be better for the environment (i.e., 83.3% preferred over resort). The collaborative product is a decision-making model that reflects the conversations between workshop participants. Structuring a participatory workshop to build a mathematical model for decision makers, as described herein, has potential application in a broad spectrum of decision-making scenarios in geoconservation and geosciences.</p>