Police said Yoshikubo is presumed dead, with no evidence of foul play.
“Investigation also revealed that Yoshikubo took steps to avoid being found,” a news release says.
Police did not say how they determined what her plans were.
Yoshikubo, 45, was a doctor who liked to travel solo.
Her disappearance prompted an extensive air and ground search. Last week, RCMP altered that search, focusing on an area north of Yellowknife using infrared equipment as well as police dogs.
The case also drew attention in Japan, drawing news crews from five different Japanese networks to the Northwest Territories.
Though the search is now over, no body has been found. Police are asking wilderness travellers to report any information that could help locate Yoshikubo's remains.
The RCMP continues to work with the Japanese Consulate on the case.