The opening two days involve medical and physical testing, with the team coming together for full training on Thursday morning at their Hilsea training base.
We’ve dipped into the picture archives to look at first days of Pompey pre-season training from the past, with a host of familiar faces in action.
Hope you enjoy the trip down memory lane far more than those players partaking in them...
5. June 2017
A Pompey triallist working with Nathan Thompson and Kal Naismith in the background in June 2017 Photo: None
6. July 2007
Sol Campbell at Pompey's pre-season return in July 2007. Picture: Steve Reid Photo: Steve Reid
7. July 2010
New Pompey boss Steve Cotterill puts his squad through their paces on the first day of pre-season in July 2010. Picture: Robin Jones Photo: Robin Jones
8. July 2013
Coach Alan McLoughlin puts Pompey's players through their paces on the first ay of pre-season training at St John's College playing fields in July 2013. Picture: Allan Hutchings Photo: Allan Hutchings