They are expecting close on 23,000 home fans. Add the 300 - 400 Cardiff fans and the attendance could get into the top three for football crowds at the stadium.
"It does not surprise me at all, with the size of support for this club, that the fans want to come and support us for this game," said Stadium Manager Rob Smith.
"We would just like to urge all the schools who have taken up the free tickets to ensure that they turn up as promised as we want as many people as possible in the ground.
"If everyone turns up we would have almost 23,000 Hull City fans in the ground, which would be a tremendous achievement.
"We have had to work extremely hard to turn this around in such a short period of time and the reward will be a sea of black and amber cheering us to victory."
Hopefully there will be 23,000 disappointed "tigers" at 4.50pm tomorrow.