A vehicle body pass-through structure is basically provided with a seal member, a rigid mounting member and a grommet. The seal member includes a first side, a second side and an access opening extending through the seal member between the first side and the second side. The rigid mounting member overlies the second side of the seal member so that the access opening of the seal member aligns with an attachment aperture of the mounting member. The grommet includes a first open end portion, a second open end portion, and a passageway extending between the first open end portion and the second open end portion. The first open end portion is disposed in the attachment aperture of the mounting member.