The continuous access to high-resolution all-weather, day-and-night large-scale synthetic aperture radar (SAR) data from the Sentinel-1 SAR, a critical satellite mission under the European Union's Copernicus program, has revolutionised satellite-based environmental monitoring applications, including three-dimensional (3D) mapping of the earth surface over the last decade. Consequently, synthetic aperture radar interferometry (InSAR) has emerged as a valuable technique for Earth’s surface Digital Elevation Model (DEM) generation using the Sentinel-1 SAR, especially in the arid and semi-arid regions. However, in the vegetated humid tropics (VHT), where InSAR holds the promise of mitigating the persistent cloud cover challenges associated with especially optical satellite-based DEM generation in the humid tropics, InSAR-DEM generation using Sentinel-1 SAR has remained challenging due to coherence constraints and the difficulties of acquiring image pairs with optimal baseline characteristics. This study assesses the impact of perpendicular and temporal baselines on Sentinel-1 InSAR coherence in VHT. The result revealed that while the optimal perpendicular baseline for achieving optimal coherence is between 201 m and 202 m, the optimal perpendicular baseline for generating InSAR-DEM with optimal precision is between 176 m and 188 m. The study also affirms the smaller the temporal baseline the better for improved coherence and precision of InSAR-DEM, with a critical temporal baseline of 36 days revealed. The findings shall provide a guide to the geoscientific community on InSAR-DEM generation and other InSAR applications with Sentinel-1 in the VHT especially on perpendicular and temporal baselines consideration.