Dogs and dog owners are increasingly present in modern urban spaces, and the construction and maintenance of urban infrastructure that includes places for them has become standard in most major cities. We wanted to investigate the extent to which the City of Zagreb is adhering to open data principles when it comes to dog-related data it makes available to citizens.The openness and quality of dog-related data was analysed in three steps. First, dog-related data was searched on various official websites and portals of the city and the data formats were ranked according to the five-star system for open data. In the second step, based on the available data, a field survey was conducted in 2020 to verify the found datasets and geocode them using a GPS device. In addition, the locations obtained from the local community of dog owners through social media were reviewed. Finally, data obtained from the survey was cross-checked with the government data to assess their quality. Government data on the locations of 300 dog waste bins and 72 green areas where dogs can be walked off-leash were available in Croatian from one or more government sources. All data sets found received the lowest score in terms of open data formats. Field survey revealed differences between the data and reality. The location of 40 dog waste bins could not be confirmed, and additional 53 bins were found that were not mentioned in the data. As for green areas, there were reportedly 10 dog parks in the city of Zagreb. The survey confirmed all locations and discovered 12 more, five of which were mentioned in the data but not designated as dog parks. The results suggest that the municipality needs to update the already open datasets more frequently. Improved implementation of these datasets into existing city data portals or the creation of a separate hub for dog owners would greatly improve the availability and reuse of this data by citizens.@en