||Park and protected area managers continue to address pressing conservation issues, such as biodiversity preservation and the prevention of species loss. However, parks and protected areas are frequently faced with financial constraints, and increasingly use ecotourism to generate financial support. One tool of ecotourism, travelers' philanthropy, is recognized as a viable method to increase funding for protected areas and conservation efforts. Travelers' philanthropy is money or time donated to a place or community by tourists that feel a responsibility to give back to the destinations they visit. Although travelers' philanthropy has been studied, there is a lack of understanding about the internal factors that motivate tourists' to donate to protected areas and conservation efforts. A better understanding of travelers' philanthropy could help increase managers' ability to generate revenue, enhance the role of ecotourism, and improve conservation outcomes. Therefore, the purpose of this study is to explore the relationships between an organization's on-site messaging and tourists' a) trust in the agency, b) caring for a species, c) on-site donation behavior, and e) intentions to donate in the future. First, in Phase 1, I conducted a content analysis of the on-site messaging (N = 24 signs). Next, based on Phase 1 results and existing scales, a quantitative questionnaire was developed during Phase 2. Finally, in Phase 3, I administered the instrument to travelers (N = 204). Data analysis consisted of scale validation, model verification, and multiple regressions derived from structural modeling. Results indicate that: 1) on-site messaging and trust influence intentions to donate, 2) on-site messaging and caring influence on-site donation behaviors and intentions to donate, and 3) an interaction exists between trust and caring. Results will help to inform Ol Pejeta's conservation funding initiatives, advance understanding about travelers' philanthropy programs, and enhance the role of ecotourism in parks and protected areas.