Basements are increasingly being used as living and working spaces, and the interest in the feasibility of using wireless devices in these environments is increasing. Therefore, it is very important to develop a propagation prediction model for basements. Especially, the isolated communication cell against the satellite or the other building will be promising due to the lack of available frequency resources. However, the propagation model for outdoor-to-basement has not been reported. Only the outdoor-to-indoor in the overground environment has been studied. Therefore, as far as our knowledge, this letter could be the first approach for the building entry loss (BEL) to analyze propagation paths to a basement from outside the building. Experiments were conducted on the basis of three different scenarios for the propagation paths between the exterior of the building and the basement. The BEL was measured at 61 and 71 dB at frequencies of 1.5 and 3 GHz, respectively; these values exceeded the value of about 30 dB of the over-the-ground model described in the International Telecommunications Union Radio-communication Sector P.2109. Further, BEL on the ground floor of the building and the penetration loss between the different floors were measured. Finally, BEL on the building side with parking lot entrance was evaluated.