The reefRover is a submersible drone that autonomously scans marine environments and enables researchers and citizen scientists to collaboratively gather well-structured image data about coral reefs at unprecedented rates. The rover is capable of both manual and autonomous operation. During a scanning mission, the rover is quickly and easily deployed from a dive boat, and once in the water, it begins to navigate a grid pattern within a geo-fenced perimeter at a fixed distance above the seabed, capturing high-resolution images of consistent scales. The images are merged to create comprehensive local maps of coral reefs. A single reefRover can cover up to 1,400 sq. meters per outing, compared to only 100 sq. meters using manual methods. By empowering a new breed non-experts explorers to generate vast collections of research-grade data, reefRover has the potential to transform coral conservation efforts in the Arabian Gulf and around the world.