Keinan has penned a two-and-a-half year deal for an undisclosed fee, and the Bluebirds will now wait to receive a work permit to finalise the switch.
Manager Dave Jones told the club`s official website: "Dekel's another quality player of international standard that we're bringing to the football club. I tried to get him here at the start of the season, but at that time he wanted to go to the Premier League which I understood.
"Sadly for him it didn't work out for him as he would have hoped as Blackpool have done well. But for the games he played in, Dekel did well and we know we are signing a player who can play at the highest level."
Ramsey has rejoined City on a month`s loan which will run until February 26 and include the game against Hull.