This year the deadline falls at 7pm on September 1, with that the cut-off until player trading recommences in the new year.
As ever, it’s been a summer where names have come thick and fast in connection with Pompey.
Some of those reported talks, some have gone on to sign for the Blues with others, well, carrying less substance.
We’ve kept our ears to the ground, so here’s every player linked with Pompey so far - with some insight into the credibility of those reports.
13. Jamal Lowe
Nothing in the transfer talk back in June after more chatter around the former Pompey man surfaced. Photo: Cameron Smith
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14. Alex Robertson
The News reported in June a Pompey return appealed ahead of talks over Robertson's Cardiff future, but the Aussie remains with the Bluebirds as he nears a return from injury. | AFP via Getty Images
15. Abu Kamara
Pompey are still admirers of the League One title winner, but is on his way to La Liga with a loan deal with Getafe lined up. | Getty Images
16. Adrian Segecic
A deal The News were right across as the Aussie became the club's first signing of the summer back in June. Photo: Dan Istitene