A triple activity system provided at a drill floor on a drillship for conducting drilling operations on a seabed beneath the drillship comprising: a first activity centre having a main well and a first top drive assembly for advancing tubular members through the main well to the seabed; a second activity centre having an auxiliary well and a second top drive assembly for advancing tubular members through the auxiliary well to the seabed; a third activity centre having an offline mouse hole for receiving an upright tubular member and an iron roughneck for making modifications to the upright tubular member assemblages received by the offline mouse hole at the third activity centre, wherein the modifications to the upright tubular member assemblages made with the iron roughneck are carried out concurrently with main drilling activities at the first activity centre and concurrently with auxiliary drilling activities at the second activity centre; a storage area adjacent the third activity centre for receiving and storing the modified tubular member assemblages and tubular members; a first delivery assembly positioned adjacent the storage area, the first activity centre, the second activity centre and the third activity centre for transferring tubular member assemblages or tubular members between the storage area and the first activity centre, the second activity centre or the third activity centre; a second delivery assembly positioned adjacent the first activity centre and the second activity centre for transferring tubular members or tubular member assemblages from the first activity centre to the second activity centre to facilitate concurrent drilling operations; a first traveling platform provided between the first activity centre and a first tubular member storage bay, the first traveling platform configured to receive tubular members from the first tubular member storage bay and configured to transfer the received tubular members to the first top drive assembly; a second traveling platform provided between the second activity centre and a second tubular member storage bay, the second traveling platform configured to receive tubular members from the second tubular member storage bay and configured to transfer the received tubular members to the second top drive assembly; and a third traveling platform provided between the third activity centre and a third tubular member storage bay, the third traveling platform configured to receive tubular members from the third tubular member storage bay and configured to transfer the received tubular members to the iron roughneck. a first activity centre having a main well and a first top drive assembly for advancing tubular members through the main well to the seabed; a second activity centre having an auxiliary well and a second top drive assembly for advancing tubular members through the auxiliary well to the seabed; a third activity centre having an offline mouse hole for receiving an upright tubular member and an iron roughneck for making modifications to the upright tubular member assemblages received by the offline mouse hole at the third activity centre, wherein the modifications to the upright tubular member assemblages made with the iron roughneck are carried out concurrently with main drilling activities at the first activity centre and concurrently with auxiliary drilling activities at the second activity centre; a storage area adjacent the third activity centre for receiving and storing the modified tubular member assemblages and tubular members; a first delivery assembly positioned adjacent the storage area, the first activity centre, the second activity centre and the third activity centre for transferring tubular member assemblages or tubular members between the storage area and the first activity centre, the second activity centre or the third activity centre; a second delivery assembly positioned adjacent the first activity centre and the second activity centre for transferring tubular members or tubular member assemblages from the first activity centre to the second activity centre to facilitate concurrent drilling operations; a first traveling platform provided between the first activity centre and a first tubular member storage bay, the first traveling platform configured to receive tubular members from the first tubular member storage bay and configured to transfer the received tubular members to the first top drive assembly; a second traveling platform provided between the second activity centre and a second tubular member storage bay, the second traveling platform configured to receive tubular members from the second tubular member storage bay and configured to transfer the received tubular members to the second top drive assembly; and a third traveling platform provided between the third activity centre and a third tubular member storage bay, the third traveling platform configured to receive tubular members from the third tubular member storage bay and configured to transfer the received tubular members to the iron roughneck.