Eagles boss Iain Dowie landed defender Mark Hudson from Fulham on a permanent basis on Saturday and has now added Speroni and Boyce to his squad.
Speroni arrives from Dundee after the Premiership new boys concurred on a fee in the region of £500,000 with the cash-strapped Scottish side.
The Argentine keeper spent three years with The Dark Blues, but will now vie for the number one jersey at Selhurst Park.
Also heading to Palace is defender Boyce, who signs for The Eagles on a free transfer after leaving Luton Town.
Boyce rejected a new contract with the League One side and has been training with Palace recently.
He clearly impressed Dowie as he has signed a deal with the club following his trial spell and will now link up with the squad for their pre-season trip to Ireland.
