Two military bases in Plymouth due to be closed have temporary reprieves while the government assesses where troops at them should be based.
Stonehouse Barracks was due to shut in 2027 and the Royal Citadel in 2024.
The closures have been put back until 2029 and 2035 respectively to determine "the future locations for units", Defence Minister Jeremy Quin said.
City MP Luke Pollard said he hoped the delays would show they were in the "right place" for those based there.
The Royal Marines base in Stonehouse, and the Army base on Plymouth's seafront, were among Ministry of Defence sites that the government announced in 2016 were to be sold to provide land for homes and raise hundreds of millions of pounds.
Mr Quin said in a letter to Mr Pollard, seen by the BBC, the closures were being delayed to work on what the "future locations for the units currently based there" should be.
He said troop moves were "big decisions" and the government wanted to give "ourselves appropriate time to consider and build as appropriate".
Mr Quin added that confirming the delays would give "greater certainty to both the commando units at the sites to prepare for their move, as well as to the local authority who we will continue to work with to assess the future potential for the sites".
Labour MP Mr Pollard said the delays were "a big step forward" in a campaign to save the bases from closure.
He said: "I hope that with these extra delays, the MoD will rightly conclude, as most of Plymouth has, that these bases are [the] right place for 29 Commando and the Royal Marines.
"We now need to see money spent on modernisation so the very best in our military have the very best accommodation and facilities too."