Some are already being redeveloped into housing, community facilities and office space - though some have been torpedoed - including the plans to relocate HMRC into the city centre, with the government unexpectedly pulling the plug on the scheme.
But many question marks also remain over a number of prime city sites where progress has either ground to a halt - or have been non-existent despite permission being given to bring sites back into use.
This comes at time when the government has ordered the city council to allow the construction of 899 homes per year between 2020-2040 - that’s 17,980 in total - meaning that the sites for housing have never been more important.
But it is not just about housing. It is about leisure and retail space - and measures which will bring about a much-needed regeneration to areas of our city which need a bit of TLC!
We take a whistle-stop tour across the city to look at 17 key sites across Portsmouth to see what the future (should) have in store for them:
5. Former Pounds Scrapyard, Tipner
Abandoned boats and submarines are being replaced with new homes as the gateway Tipner East site is now well on the way to being developed. The former Pounds Scrapyard site - one of the first things you see as you enter the city via the M725 and finding someone willing to take it on to develop it has been a challenge. But now Vivid is transforming the site to 800 homes and community facilities - as well as constructing new sea defences in the area and creating wildlife habitats. The initial works to clear the cite are complete - so now construction can begin! Photo: Submitted
6. Fraser Range, Eastney
The six-and-a-half acre Fraser Range site in Eastney was home to a 20th-century military training and experimental facility, it was closed in 2006 and has remained vacant ever since. Now plans have been approved to transform it into 134 new homes across seven blocks. The homes will primarily be flats, ranging from one to three bedrooms, alongside seven houses and two duplexes. We are now just waiting for work to begin! | Shaun Roster
7. Former St John's College, Southsea
The former independent school closed in the summer of 2022 due to falling student numbers and has been vacant ever since. However, planning permission has been granted for 49 one-bed flats, 138 two-bed, 24 three-bed and one four-bed and works are under way. Picture: Sarah Standing (050623-5343) Photo: Sarah Standing
8. Pryzm Portsmouth
Pryzm closed with immediate affect at the beginning of last year as part of a growing shift in the night time economy away from traditional clubbing. No plans are yet know for the listed building which was also once known as Connaught Drill Hall (TA Centre) Photo: Pryzm Portsmouth