In a method of operating a storage device including a non-volatile memory (NVM), the non-volatile memory including a memory cell array, the memory cell array including a first plane and a second plane, the method includes receiving a read command set for data sensing of the first and second plane; simultaneously loading first page data stored in the first plane into a first page buffer of the first plane and second page data stored in the second plane into a second page buffer of the second plane based on the read command set; receiving a data output command set that includes the first plane; and continuously transmitting the first page data and the second page databased on the data output command set.