VesselFinder.com, which tracks marine ship movements, located the Danish patrol boat P525 at about one nautical mile away from the Chinese-flagged ship on Thursday morning Europe time.
After four weeks of surveillance, Danish naval ships have left the Kattegat area, where the Chinese vessel Yi Peng 3 remains anchored.
The 80-year-old boat was hauled to Florida Holocaust Museum, ready for its debut when the museum finishes renovations.