Goalkeepers Joe Lewis and Neil Alexander and defender Callum Morris have joined Aberdeen.
Lewis, 28, spent last term on loan at Fulham from Cardiff City and has signed a two-year contract at Pittodrie, while Morris, 26, has agreed a one-year deal.
Alexander, 38, moves to Pittodrie after leaving Hearts and will compete with Lewis for the number one jersey.
Lewis told Aberdeen's website the club's upcoming Europa League qualifiers "were a massive attraction".
"Hopefully we can get through the first few rounds and get as far as we can," added the Englishman.
Capped five times by England's Under-21 side, Lewis was twice an unused substitute for the senior side while playing his club football at Peterborough United.
On-loan Liverpool goalkeeper Danny Ward was Aberdeen's first-choice keeper for the first half of last season but he was recalled to Anfield in January.
Adam Collin, on loan from Rotherham United, Scott Brown and Aaron Lennox also featured in goal for Derek McInnes' side as the Dons finished the season as Scottish Premiership runners-up.
"A lot of goalkeepers when they get into their late 20s and 30s become better players so hopefully I can do the same," Lewis said.
Morris spent two seasons at Dundee United after a switch from Dunfermline Athletic. He made 15 appearances last season as United were relegated, with his campaign interrupted by injury.
He can operate in central defence or at right-back and has played up to Under-21 level for Republic of Ireland.
"What an opportunity it is for me," said Morris. "I am really looking forward to the European games starting later this month.
"I got a call from my agent to say the manager had been in touch. As soon as I heard that, I had my mind set on coming up here.
"It is obviously a huge club with a very good squad and they showed that when they pushed Celtic all the way last season."
Find all the latest football transfers on our dedicated page.