Jacob Olsen moved with his wife to Copenhagen in the early 1970s, where he continued his translation work, and gave private lessons in English until his death of natural causes on 13 October 1994 at the age of 90 years.
Jacob Olsen flyttede sammen med sin hustru til København i starten af 1970'erne, hvor han fortsatte sit oversættelsesarbejde samt gav privatundervisning i engelsk lige indtil hans naturlige død den 13. oktober 1994, 90 år gammel.