Hull City have signed Brighton full-back James Furlong and Aston Villa winger Jaden Philogene for undisclosed fees and Liverpool midfielder Tyler Morton on a season-long loan.
Philogene, also 21, has had previous loan spells in the Championship with Stoke and Cardiff.
Morton, 20, made 46 appearances during a loan with Blackburn last season.
The Tigers have also signed Fenerbahce forward Bora Aydinlik, 18, on a season-long loan and he is set to join up with the club's academy side.
Find all the latest football transfers on our dedicated page.