Given 38,956 tickets to sell, Hull have handed back an undisclosed number of those, although opponents Sheffield Wednesday have sold out their 38,889 allocation.
Wednesday supporters have also bought up a number of additional seats to cope with demand, once it became clear Hull would be unable to pack out their section of the stadium.
But, much to the Owls’ fans frustration, they could not buy up all of Hull’s spare seats, due to the need to segregate supporters of each side.
A Football League spokesman said: “With ticket sales for Saturday’s Sky Bet Championship play-off final having now ceased, it has been confirmed that a number of tickets from Hull City’s allocation have remained unsold meaning that there will be empty spaces in the crowd.
“As with previous matches at Wembley, it isn’t always possible to make all of one club’s unsold tickets available to fans of their opponent, as the stadium’s safety certificate requires supporters to be separated at the turnstiles and on the concourses, as well as in the stadium bowl itself.
“Throughout the week, the League, Hull City and Wembley Stadium have explored all options in order to make some additional tickets available to Sheffield Wednesday supporters. As a result, a number of tickets were provided to Wednesday fans through a ballot organised by the club.”
The game kicks off at Wembley at 5pm, with a much-touted financial ‘prize’ of £200m on offer for whichever team makes it to the Premier League come Saturday night.