This study is addressed to evaluate the hydrodynamic forces experienced by multiple flexible cylinders arrays which are free to oscillate due to water crossflows. This paper presents a part of experimental results of two different configurations of three flexible circular cylinders which were towed in still water. The cylinders were submerged partially into the still water from a towing carriage as hanging-off vertical cantilevers. Each cylinder has length-to-diameter ratio of 34.4 with low mass ratio (= 1.24). The Reynolds number varied from 1.08 × 104 up to 3.78 × 10 4. A longitudinal gap between upstream and downstream cylinder (LUD) was varied by 5D, 7D, 9D, and 10D, respectively. The measurement of the hydrodynamics forces in two, inline (drag force) and transverse (lift force) directions were performed simultaneously. Frequency of the drag force was found approximately twice the corresponding lift force frequency at the related reduced velocity (Ur) for all cases, except at low Ur, and linearly increased as a function of the Ur. The variables Ur and L UD revealed have significant influence on the characteristics of CD and CL for each test configuration. For upstream cylinders in both two configurations, there are basically three distinct regions dealing with the CD and CL characteristics as function of Ur, while for downstream cylinders the CD and CL decreased as Ur and LUD increased. At the medium Ur, the configuration with two cylinders at the downstream position (Case B) produced higher total drag and lift coefficients on the downstream cylinders than another one.