The Samsung Galaxy M31 sports a big 6.4-inch display The Galaxy M31 is comfortable to hold in the hand but is a little heavy at 191g. The weight of the smartphone is mainly because of the big 6,000mAh battery that it packs. The Galaxy M31 is a dual SIM device with support for 4G as well as VoLTE. It runs Samsung OneUI 2.0 on top of Android 10. We found the Galaxy M31 to have a fair amount of bloatware onboard. The Galaxy M31 has a quad-camera setup at the back with the primary being a 64-megapixel shooter. It also houses an 8-megapixel ultra-wide-angle camera, a 5-megapixel macro camera, and a 5-megapixel depth sensor.