It is still a challenge to understand the mangrove dynamics and their response to the environmental forces. The assessment of the mangrove dynamics can be obtained by observing the development of its biophysical properties. This observation will provide insights into the processes at the plot level and landscape level. In this research, the assessment has been conducted by integrating Unmanned Aerial Vehicle (UAV) photogrammetry with the Structure from Motion (SfM) method and multiple satellite imagery sources. The objectives are to retrieve the mangrove biophysical properties based on two periods of UAV observation (2019 and 2021) and estimate the extent and the age-height relationship of the mangrove forests for twelve years. The analysis resulted in an accurate individual tree structure and mangrove age distribution. We integrated UAV-based very high-resolution 3D point clouds and the classified mangrove extent based on the combinations of satellite imagery from four satellites (Landsat 7-8 and Sentinel 1-2). The point clouds were processed by noise removal, ground classification, height normalisation, and generating the Canopy Height Model (CHM) to detect the individual tree height and location. Google Earth Engine has been used to perform the mangrove classification by way of four vegetation indices, i.e., Normalised Difference Index, Normalised Difference Moisture Index, Enhanced Vegetation Index, and Soil-Adjusted Vegetation Index. The off-the-shelve UAV-based surface model had a total error of 0.06m compared to the ground control points, and the root mean square error of the individual tree was 0.23m. GEE’s mangrove classification resulted in the three-monthly mangrove extent map —an advantage over the commonly annual mangrove extent map. The UAV-derived height information and satellite-based mangrove age class were integrated to retrieve the relationship of mangrove height dependent on the stand age. We observed the seasonal pattern of mangrove expansion. The mangroves area receded during the transition from dry to wet season and regrow during the wet to dry season. The general trend is the expansion of the mangroves with the high-low seasonal signal that is likely related to the mangrove’s response to sediment deposition and freshwater.