The San Frediano bell tower in Lucca, dating back to the thirteenth century, is located in the historic center of Lucca and is about 50 m high. This dataset hosts the velocities recorded on the tower from 29-5-15 to 3-6-2015 under ambient vibrations. The velocities were recorded by four tri-axial seismic stations installed at different positions along the tower's height. Data have been acquired continuously with a frequency of 100 sp. The recordings hosted in the dataset are given in count and can be transformed to m/s using the constant 119*10^-9 /200. This constant allows for a good approximation of the velocity values in the frequency range of interest. For more information on the transfer function of the instruments, please get in touch with the Authors. Data were acquired in the MONSTER and the SOUL project frameworks, both funded by the "Fondazione Cassa di Risparmio di Lucca", whose contribution is gratefully acknowledged.