Is the coffee cup leak-proof? No, the coffee cups are not leak proof. The lids, whilst preventing major splashes if knocked over, do have holes in them for drinking that cannot be closed that will leak if not stored properly. Have more questions? Submit a request 1 Comments Date Votes 0 Pilar January 09, 2019 10:21 Sería interesante un tapa para el vaso de café y no derramar su contenido en el transporte. Tiene poca utilidad sin tapar herméticamente Please sign in to leave a comment.