Portsmouth have signed goalkeeper Josef Bursik from Club Brugge and 21-year-old striker Makenzie Kirk from St Johnstone for undisclosed fees.
Pompey have also sealed a permanent deal for Crystal Palace academy winger Franco Umeh and loaned forward Conor Chaplin from Ipswich Town for the rest of the season.
Bursik has agreed a two-year-deal at Fratton Park, having made 53 appearances for Stoke City in the Championship before moving to Belgium in 2023.
The 25-year-old played for England at under-21 level and had EFL loan spells at Accrington, Doncaster, Peterborough and Lincoln.
Stoke loaned Bursik to Scottish Premiership club Hibernian last season but he failed to make an appearance.
Blues boss John Mousinho said: "He's someone who showed a lot of promise as a youngster and has played plenty of Championship games.
"Josef really bolsters the options we've got in the goalkeeping department and is a target that's been in our sights for a while now, so we're delighted to get the deal done."
Northern Ireland under-21 international Kirk has signed a three-year contract.
The 21-year-old came through the Hearts academy and played for Hamilton's youth sides. During his time at St Johnstone, he scored 14 goals in 50 appearances.
Mousinho said: "We're bringing in a player who's an incredibly exciting young prospect and has already featured in plenty of first team games up in Scotland.
"As well as being one for the future, we believe he's someone who can have a positive impact on the side right now.
"We're very excited to have Makenzie in our squad. I'm looking forward to working with him and watching him continue to develop."
