Provided are a storage device configured to perform high-speed link startup and a storage system including the storage device. The storage system performs data communication through a connected transmission lane and a connected reception lane from among a plurality of lanes between a host and the storage device. The host transmits an activate period of the connected transmission lane, which is less than a first time period, to the connected reception lane, and the storage device receives the activate period of the connected reception lane, which is less than the first time period. The host and the storage device perform link startup in a high-speed mode through the connected transmission lane and the connected reception lane, based on the activate period being less than the first time period.