The Blues have so far recruited 11 new faces this summer with Marlon Pack, Colby Bishop and Dane Scarlett the pick of the bunch.
With his side still in the market on the final day of the window, there’s still plenty of anticipation ahead of the 11pm close.
After the formation of the transfer window in the 2002-03 campaign, deadline day has been well-known to Pompey fans whether it was in the Premier League days with Harry Redknapp or with Paul Cook in League Two.
We’ve taken a look at 10 standout signings who were memorable for all types of reasons - even if it didn’t work out on the pitch!
Here’s what we found.
5. Glen Johnson
Johnson spent the 2006-07 campaign on loan with Pompey before making his move permanent on deadline day in August 2007. The right-back arrived from Chelsea in a £4m deal, which saw him sign a four-year contract. The ex-England international appeared 72 times after he signed permanently, which also saw him win the FA Cup in 2008. Photo: Clive Rose
6. Papa Boupa Diop
The central midfielder joined alongside Johnson on deadline day in August 2007 as he arrived from Fulham for £3.5m. After penning a five-year deal at Fratton Park, the former Senegal international made 72 outings for the Blues and also won the FA Cup before departing in 2010. Diop unfortunately passed away in 2020. Photo: Bryn Lennon
7. Jermaine Defoe
The striker arrived at Pompey on deadline day in January 2008 for £7.5m from Spurs. The striker had an impressive - but short - stay at Fratton Park, scoring 17 goals in 36 outings. The former England international made a return to White Hart Lane 12 months later after controversially leaving PO4 in January 2009. Photo: Jonathan Brady
8. Mike Williamson
The centre-back joined the Blues on September 1, 2009 after making an initial £2m move from Watford, which rose to £3m. However, Williamson failed to make an appearance for Pompey before joining Newcastle six months later. His switch has been regarded as one of the worst moves in recent years. Photo: Mark Runnacles