Singapore is one of the most densely populated countries in the world, but it is surprisingly “green”. Wild smooth coated otters (Lutrogale perspicillata) have returned to Singapore in recent years, and now several families of otters live in both the inland and coastal areas of Singapore, including in the heart of the downtown region. We used a combination of citizen science and focal animal sampling video recordings to document otter behaviours, and in so doing also documented many interactions between otters and people in Singapore. Here we describe a series of events involving lost pups, injured otters, natural conflict between otter families and the public’s reaction, and detrimental interactions between otters and people as well. We describe how citizen science can allow the public and academic institutions to collaborate and contribute to municipalities in helping to coordinate and interact with a wild urban predator. We find that a minimum number of stakeholders are generally needed to be effective.