The carcass was first spotted off Laem Sai Bay at Koh Racha on Saturday (Oct 29).
DMCR officials, working with officers from the Phuket Marine Resource Conservation Center, the Department of Fisheries and other agencies, brought the remains back to Rawai, in Phuket, yesterday.
The remains were confirmed to be of an adult female Bruda whale, some 13 metres long.
The whale was in an advanced stage of decomposition, making it difficult to determine the cause of death, DMRC officers noted.
The whale was estimated to have died some three to four weeks before its remains were found, officers added.
One plastic cup was found in the middle section of the small intestine, but did not cause intestinal obstruction, officers noted.
The condition of the remains have so far left experts unable to confirm the cause of death. They are continuing their examination, the DMCR reported.
People were asked to report any similar discoveries by calling the 24-hour hotline 1362.