This paper reports on a methodology scan a clast in the field using iPhone LiDAR and to post-process the scan into a 3D watertight model (useful for volume estimation). This methodology uses Scaniverse to scan clasts in the field and then post-process the LiDAR scans using Blender. Post-processing includes ensuring there are no holes in the boulder mesh so it is watertight. Then, the volume of the 3D model can be calculated. This pipeline was tested on 36 coastal limestone boulders on Inishmaan, Ireland. From the processed scans, volumes were computed and compared with field measurements of the shortest, intermediate, and longest boulder lengths (a-, b-, and c-axes). Results found that the 3D model volumes were smaller than those calculated using the field axes volume method. Additionally, the volume coefficient (CV) for each boulder was found to differ by shape. This paper presents CV values for the following boulder shapes: block elongate, block flat, blade, equant, plate, slab, sub-equant. This low-cost method and time-efficient approach allows for volume estimation to be implemented widely and efficiently in coastal boulder studies on rocky coastlines.