The Titan submersible's catastrophic implosion was caused by the Polar Prince, which has now returned to Canadian shores and is the subject of an investigation.
The ship's flags were lowered to half-mast as it berthed in St. John's, Newfoundland, on Saturday.
The Titan's launch platform was being towed by another vessel in the harbor.
All five occupants of the Titan died when it broke apart while on a dive to the Titanic wreck.
About 400 miles from St. John's, in the North Atlantic, where the Titanic sank, the Polar Prince towed the submersible there.
Once it lost contact about an hour and a half into its dive on Sunday, it was actively involved in the search for the vessel while carrying members of the support team and some victims' families.
About 1,600 feet (487 meters) from the bow of the Titanic wreck, pieces of the submersible were discovered on Thursday.
The start of a safety investigation was announced by Canada on Friday. There may be participation from government agencies from other nations, but it is not yet clear who will be in charge of the investigation.
Authorities will examine the materials used to construct the sub's outer walls in addition to the Polar Prince's role, according to experts.
Industry experts have come forward since the accident's news broke to say they had concerns about OceanGate's safety procedures. OceanGate owned the Titan, and its CEO Stockon Rush was on board when the accident occurred.
In emails obtained by the BBC, Mr. Rush was seen dismissing one expert's concerns as "baseless cries.".
Hamish Harding, Paul-Henry Nargeolet, Suleman Dawood, and Shahzada Dawood were also passengers on the Titan.
