In May 1966, her five-year loan was renewed for $1 million, and the sub underwent a refit in 1967 for $1.2 million. In Spring 1968, "Grilse" was sent on a training cruise to Japan. Once there, the boat trained with units of the Japanese Maritime Self-Defense Force and the United States Navy. In 1968, the Canadian Navy, now called Maritime Command, was offered a more modern by the US. Maritime Command chose to accept the offer and was purchased as a direct replacement for "Grilse" on the west coast.