The movement of nutrients is central to ecological processes. Ecological management has historically been constrained to the boundaries of the ecosystem in question. However, allochthonous inputs across ecosystem boundaries (ie. marine nutrients entering terrestrial food webs) can have profound effects on the recipient ecosystem. Understanding the trophic pathways by which marine subsidies move into the terrestrial environment are important for proper management of coastal habitats. This study examined the use of marine nutrients by small mammals on the Jack and Laura Dangermond Preserve, California. We quantified the use of marine subsidies using stable isotope analysis of fur and whisker samples from small mammals captured at beach and inland sites. We found that coastal small mammals were being subsidized by marine nutrients and had wider dietary niche widths than their inland counterparts. These marine subsidies can bolster small mammal populations in drought years and could in turn subsidize terrestrial consumers higher up on the food web. Coastal ecosystems are being disproportionately impacted by climate change, so understanding nuances of coastal processes is paramount to maintaining ecosystem functionality in the future.