Arboreal gastropods comprise an important component of the mangrove benthic faunal community, and their composition and distribution patterns are affected by the characteristics of mangrove vegetation. Therefore, following the mangrove rehabilitation, the dynamic of gastropod community is strongly related to the development of vegetation. As one of the few gastropods highly associated with mangrove habitats, snail species of Mainwaringia genus belonging to the Littorinidae family are widespread in Asian mangroves. However, there are few studies on the distribution and population characteristics of Mainwaringia species in mangroves, and information of the dynamics of Mainwaringia population following mangrove rehabilitation is even scarce. In this study, we investigated the distribution and temporal dynamics of abundance of a newly recorded species, Mainwaringia leithii, in young Kandelia obovata stands in the early rehabilitation stage in Xiatanwei, Xiamen City, China. The density and abundance of M. leithii snails, and the vegetation characteristics were continuously measured since 0.5-a after plantation of K. obovata using propagules at the mudflat. The plant height, crown diameter, basal stem diameter and canopy coverage of K. obovata were 41.3 cm, 25.0 cm, 1.04 cm and 25%, respectively at the 0.5-a-old stand, and increased to 179.2 cm, 76.7 cm, 5.96 cm and 95%, respectively, at the 8-a-old stand. M. leithii individuals were found soon after the mangrove rehabilitation (i.e., 0.5 a), with respective density and biomass of 12 ind/m² and 0.29 g/m². The M. leithii population reached a maximum abundance at the 1.5-a-old stand, and their density and biomass were 136 ind/m² and 1.86 g/m², respectively. Nevertheless, the present study recorded a decrease in the abundance of M. leithii snails in the subsequent sampling campaigns, i.e., the density decreased to 61 ind/m² in the 2-a-old stand, while it was even more less, with no more than 10 ind/m² at the 8-a-old stand. The shell height of M. leithii samples collected in this study ranged from 1.90 to 8.14 mm, and 80% of the samples fell into a range between 3 mm and 7 mm. The shell height of snails presented a temporal change in association with the stand age and snail density. Small-sized M. leithii snails, with a shell height between 3-6 mm comprised a large proportion (-70%) of those collected at the 1.5-a and 2-a-old stands, wherein the snails occurred in large numbers. Contrarily, at mangrove stands with other age classes (except at the 8-a-old stand) where low snail densities were measured, the larger snails with shell height >6 mm dominated the M. leithii population. The present study found a quadratic increase in the individual weight with the shell height of snails. These results suggest that M. leithii can be a common and abundant arboreal gastropod species in the mangroves, and its recruitment occurs in rapid response to the establishment of mangrove vegetation. The temporal variation of its abundance with stand age in the early stage of rehabilitation may be partly attributed to the change in its habitat characteristics related to the development of mangrove vegetation. Regarding that the information of this species is still scarce, future studies should give more attention to the ecology of this species in mangrove forests.