The benefits and services of urban gardens (UGs) in urbanized areas are being increasingly recognized, leading to widespread enhancement of efforts in protection and provision. At present, several types of UGs created under the policy of “The Garden City Initiative” (GCI) exist in Taipei City, Taiwan, and four types of UGs, namely Allotment Garden (AG), Happy Garden (HG), Rooftop Garden (RG), and School Garden (SG), have been created using vacant lots and rooftop spaces developed via GCI. To clarify the characteristics of UGs in Taipei City, this paper first analyzes the changes in the number and surface area of each type of UG during 2015–2019. Second, using the 2019 data on all 201 UGs (18 AGs, 107 HGs, and 76 RGs) and excluding SGs that are only accessible by school students, this paper clarifies the spatial distribution of UGs in each district of Taipei City and the accessibility of UGs to locals and non-locals using a geographic information system. Furthermore, correlations between the accessibility of UGs to both locals and non-locals and their surface areas were evaluated. As a result, positive correlation was observed between the accessibility of UGs to locals and non-locals in seven districts, suggesting that both locals and non-locals have equal access to UGs. Lastly, the characteristics of UGs realized in Taipei City under GCI and their accessibility to locals and non-locals are discussed and conclusions are drawn on the implications for the utilization of vacant lots and rooftop spaces as UGs.