Marlon Pack became Pompey’s first acquisition of the summer, returning on a free deal from Cardiff.
The 31-year-old was soon followed by the arrivals of Zak Swanson, Joe Rafferty, Josh Griffiths, Joe Pigott and Josh Oluwayemi before Colby Bishop became the latest name to join the ranks after joining for an undisclosed fee from Accrington.
In total, seven fresh faces have arrived through the door at Fratton Park, while Marcus Harness remains the only name to depart.
But how does the Blues’ summer transfer business compare to their League One rivals?
We’ve taken a look at the most – and least – active clubs in the third tier so far this window.
Here’s what we discovered.
9. Peterborough
Number of signings: 5; Signings: Ben Thompson (Gillingham - free), David Ajiboye (Sutton - undisclosed), Hector Kyprianou (Leyton Orient - undisclosed), Harvey Cartwight (Hull - loan), Lucas Bergstrom (Chelsea - loan). Photo: Pete Norton
10. Accrington
Number of signings: 5; Signings: Shaun Whalley (Shrewsbury - free), Matt Lowe (Brackley - free), Mo Sangare (Newcastle - free), Lukas Jensen (Newcastle - loan), Ryan Astley (Everton - free). Photo: Naomi Baker
11. Plymouth
Number of signings: 5; Signings: Mickel Miller (Rotherham - free), Matt Butcher (Accrington - free), Morgan Whittaker (Lincoln - loan), Finn Azaz (Aston Villa - loan), Bali Mumba (Norwich - loan). Photo: Alex Pantling
12. Burton
Number of signings: 5; Signings: Victor Adeboyejo (Barnsley - free), Davis Kiellor-Dunn (Oldham - free), Calum Butcher (Dundee - undisclosed), Viljami Sinisalo (Aston Villa - loan), Quevin Castro (West Brom - loan). Photo: Jan Kruger