Photos shared online show a heavily corroded, track-like structure partially exposed along Xuan Dieu Beach on April 17, when unusually low tides revealed the object.
Local authorities said initial observations suggest it is part of a tank long buried beneath the seabed.
Some observers believe the remains may belong to a US-made M41 Walker Bulldog, though authorities have yet to confirm its origin.
Quy Nhon Ward’s Culture and Social Affairs board said any recovery effort would require coordination with provincial military authorities due to technical challenges.
The site is known to contain wartime relics. In 2007, two tanks were recovered from the same area, believed to have belonged to an armoured battalion of the South Vietnamese regime. They were reportedly destroyed during a retreat on March 31, 1975, at Quy Nhon military port and later buried under sand for decades.