A splash prevention device, mounted on top of the breathing tube of a snorkel, including a housing having an oblique opening in communication with the breathing tube, a U-shaped pivotal member pivotally mounted on the housing, a float member pivotally located on two ends of a cross member of the pivotal member and including a top stop, a pivotal cover pivotally located on the cross member and including a tab and a projection at both ends, and a mask partially enclosed the housing and mounted thereon. The float member and the pivotal member pivot about the housing and the pivotal cover pivots about the cross member when the splash prevention device is submerged below a water surface. The pivotal actions are stopped when the opening is closed by the projection of the pivot cover to prevent splashed water from entering the breathing tube of the snorkel.