Hull City have brought in Wigan midfielder Leonardo Da Silva Lopes, Leicester defender Callum Elder, Bolton forward Josh Magennis and Everton's Matthew Pennington on deadline day.
Da Silva Lopes, Elder and Magennis have all signed permanent deals for undisclosed fees while defender Pennington has agreed a season's loan.
Da Silva Lopes, 20, and Elder, 24 have signed three-year contracts.
Northern Ireland striker Magennis, 28, has agreed a two-year deal.
The club has an option to extend the contracts of all three of their permanent signings for a further year.
Pennington, 24, spent last season on loan at Ipswich Town and played 24 times for Leeds in the 2017-18 season.
He has also played seven Premier League games for Everton, scoring in the 3-1 loss at Liverpool in April 2017.
Lopes moved to Wigan for an undisclosed fee a year ago from Peterborough United, but made just three appearances and spent the second half of last season on loan at Gillingham.
He made 108 appearances for Posh having come up through their academy and played under Hull's former Peterborough boss Grant McCann at London Road.
Magennis scored seven goals in 44 games for Bolton last season having made a summer move from Charlton Athletic, while Australian left-back Elder has not played a game for Leicester but has had loans at six clubs including Ipswich Town, Wigan and Barnsley.