Pompey have agreed one-month contracts with 10 players ahead of their season opener against Bournemouth.
Kieran Djilali, Mustapha Dumbuya, Jon Harley, Brian Howard, Izale McLeod and Lee Williamson have all agreed to join the Blues ranks, while Simon Eastwood, who played at Plymouth on Tuesday, has signed after originally penning a non-contract deal.
Jack Compton, Luke Rodgers and Liam Walker have signed subject to international clearance.
All the deals are subject to Football League and FA approval.
Londoner Djilali came through the academy at Crystal Palace.
The 21-year-old played twice against Pompey in 2010, in a League Cup tie at Fratton Park which the Blues won on penalties and Palace’s 4-1 win at Selhurst Park in September.
The right-sided player had a loan spell at Chesterfield and spent last season at AFC Wimbledon.
Dumbuya broke into professional football with Doncaster after impressing for several non-league sides.
The speedy right-back joined Rovers in 2009 and spent three years at the Keepmoat Stadium, playing 36 times.
The 25-year-old, who played two games on loan at Crystal Palace last season, came off the bench for Doncaster in their 4-3 defeat to Pompey in April.
Harley has joined Pompey more than a decade after first being linked with them.
The full-back was at Chelsea when Blues boss Graham Rix, his former youth team coach, wanted to bring him to Fratton Park.
Harley joined Fulham and the 32-year-old has since had permanent spells at Sheffield United, Burnley, Watford and Notts County.
Howard will be Pompey’s new captain.
The midfielder, who has spent the last three seasons at Reading, was loan at Millwall for part of last season and played in their 1-0 win over Pompey at The Den on Boxing Day.
Winchester-born Howard made his debut for Swindon in 2003 and after 70 games moved to Barnsley.
The 29-year-old scored 29 goals in three seasons at Oakwell before switching to Sheffield United for a season.
McLeod scored 32 goals in 73 games during two seasons at Barnet, starring in their League Cup win at Pompey last season.
The 27-year-old former England under-21 international began life at Derby before notching a goal in every other game in three seasons at MK Dons.
A £1.1m move to Charlton followed, with the striker having loan spells at Colchester, Millwall and Peterborough before his switch to Barnet.
Lee Williamson is the only capture who has not featured for Pompey in pre-season.
The midfielder has spent the last three seasons at Sheffield United, scoring 19 goals in 76 appearances.
Starting life at Mansfield, the 30-year-old has also had spells at Northampton, Rotherham and Watford, and in 2008 was called into the Jamaica national squad.
Goalkeeper Eastwood, 23, came through the ranks at Huddersfield – enjoying loan spells at Woking and Bradford – and spent last season at Conference North side Halifax.
The Luton-born player has been capped by England at under-18 and under-19 level.
Compton returns to Fratton Park six years after leaving the club as a youngster.
The left-sided midfielder had two years at West Brom before a spell in non-league football was followed by a move to Scottish side Falkirk in 2010.
Compton, 23, made 37 appearances for Falkirk and last season had loan spells at Bradford and St Johnstone.
Rodgers spent the bulk of 2011 with Major League Soccer outfit the New York Red Bulls, scoring nine goals in 23 games alongside strike partner Thierry Henry.
The 30-year-old striker from Birmingham played 176 times for Shrewsbury before spells at Crewe, Port Vale and Yeovil.
In 2010 Rodgers helped Notts County to promotion under former Blues boss Steve Cotterill and most recently played seven games for Norwegian side Lillestrom.
Walker impressed Pompey when playing for the Gibraltar national side in a pre-season friendly last month.
The 24-year-old midfielder, whose family are Pompey fans from Waterlooville, had trials with Manchester United, Everton and Aston Villa as a teenager.
Walker, who was top scorer for Spanish side San Roque last season, scored a screamer in Pompey’s 2-0 friendly win at AFC Wimbledon earlier this month.