The 23-year-old has signed a new two-year contract at St James’ Park, before finalising his switch to south Wales in a bid to prove to new head coach Steve McClaren he has a future on Tyneside.
A Newcastle statement read: “Sammy Ameobi has joined Cardiff City on a season-long loan deal, after signing a new contract with Newcastle United.
“The 23-year-old winger has put pen-to-paper on a two-year deal at St. James’ Park, and will now spend the 2015/16 campaign in South Wales, turning out for the Cardiff in the Championship.”
Ameobi, younger brother of former Newcastle striker Shola, has made 21 league starts for the Magpies since making his debut against Chelsea four years ago.
The former England U21 international had a spell on loan at Middlesbrough three seasons ago, scoring once in nine appearances.