Aims: This study explores the microbial diversity of sources which may influence boat microbial communities. We investigated the impact of dock, air and water microbial communities on the hull, transom and bilge microbial communities over the span of 11 days. Methods and Results: Using source tracking software, we investigated the extent to which each of our potential sources (air, water and dock) influenced the overall microbial community. This study concluded that the dock impacted 14-64% of the hull and transom microbial community. Micro-organisms from the water were shown to impact 5Á6% the bilge microbial community but had minimal impact on hull and transom microbial communities. Micro-organisms from the air had minimal impact in all areas of the boat. Conclusions: Our results demonstrate that micro-organisms from sources other than water can influence the microbial community of a boat, suggesting that terrestrial micro-organisms can impact the boat microbial community. Significance and Impact of the Study: Outside of ballast tanks, microbial diversity on boats is largely unexplored. While ballast water is widely recognized as a route for dispersal of allochthonous micro-organisms, comparatively little is known about the microbial diversity on other areas of the boat. If the organisms on a boat originate from sources other than water, there is potential that terrestrial micro-organisms could be dispersed by shipping activity.