The present invention relates to a subsea multipiston pump module, a subsea multistage pump and skid, having two reciprocating pistons controlled by a control means in such a way that the pistons can be driven either in a parallel mode, where the pistons are driven in phase with each other, or in a serial mode, where the pistons are driven out of phase with each other, wherein the pistons are fluidly connected with each other by a piston connection means in such a way that in parallel mode they are fluidly connected in parallel, and in serial mode, they are fluidly connected in serial. Further, the invention relates to a method of pumping a media fluid under subsea conditions.