A memory system, which is connectable to a host, includes a non-volatile memory and a controller configured to store data in the non-volatile memory and in a memory region within the host and read the data from the memory region within the host. The controller includes a first encoding/decoding circuit configured to execute encoding/decoding with a first encoding scheme, a second encoding/decoding circuit configured to execute encoding/decoding with a second encoding scheme having a higher error correcting capability than an error correcting capability of the first encoding scheme, an encoding scheme selecting circuit configured to select an encoding/decoding circuit from the first encoding/decoding circuit and the second encoding/decoding circuit to perform encoding of data to be stored in the memory region, based on information about the data read from the memory region.