Abstract: A riser system and method including a bore submerged surface package of valves, a cross over assembly with a high pressure-low pressure connector connected to the bore submerged surface package of valves, a high pressure insert, and a telescoping flow tube. The riser system also include a high pressure bore subsea stack, a low pressure slip joint, a tension ring, a flex joint, a diverter, a mandrel capable of interfacing with the high pressure-low pressure connector, a high pressure mandrel crossover and at least one high pressure insert riser joint, a high pressure-low pressure latch, a telescoping flow tube telescopic conduit, at least one telescoping flow tube latch, a telescoping flow tube low pressure flex joint, a telescoping flow tube main housing, or a rotating control device.