In complex with KIF2C, constitutes the major microtubule plus-end depolymerizing activity in mitotic cells. Its major role may be to transport KIF2C and/or MAPRE1 along microtubules (By similarity). Interacts with MAPRE1; this interaction is required for efficient accumulation at microtubule plus ends. Interacts with KIF2C at microtubule tips; this interaction increases the affinity of both partners for microtubule plus ends and is required for robust microtubule depolymerization. KIF2C phosphorylation by AURKA or AURKB strongly reduces KIF18B-binding. Present predominantly in the nucleus and to a lesser extent in the cytoplasm of interphase cells. During mitosis, found to be closely associated with astral microtubule plus ends emanating from the spindle pole during prometaphase and metaphase (By similarity). Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Kinesin family.