Abstract: Folding trimaran which is symmetrical in relation to its median longitudinal axis and comprises a central hull, equipped with a mast, and also two lateral floats, which are connected to the central hull by at least one connecting arm. The trimaran can be moved between a first position in which the connecting arms are unfolded approximately horizontally on each side of the central hull, substantially perpendicularly to the longitudinal axis of the latter, and a second position in which the floats are folded along the central hull in such a manner as to reduce the space requirement. The trimaran has at least two connecting arms arranged symmetrically to define a maneuvering pair extending as far as the median horizontal axis.