Seven people have been arrested on suspicion of seizing control of an oil tanker, police have said.
The men were detained when military forces stormed the Nave Andromeda which was thought to have been hijacked off the Isle of Wight on Sunday night.
Sixteen members of the Special Boat Service (SBS) ended a 10-hour stand-off which started when stowaways on board the ship reportedly became violent.
Defence Secretary Ben Wallace said there had been a "threat to life".
Hampshire Constabulary said the seven men were being held on suspicion of "seizing or exercising control of a ship by use of threats or force under Sections 9(1) and (3) of the Aviation and Maritime and Security Act 1990".
"All 22 crew members are safe and well and the vessel is now alongside in the port of Southampton," a spokesman said.
Investigators are now speaking to the ship's crew to establish what happened.