The Black Cats defeated Sheffield Wednesday in the play-off semi-finals to book their place at Wembley while Wycombe overcame MK Dons.
Wigan Athletic and Rotherham United secured the two automatic promotion spots.
This season was the first campaign that supporters returned in their numbers after Covid-19 restrictions stopped fans attending games the previous campaign.
Many clubs saw their away support rise on average over the campaign, as fans racked up the miles following their teams.
Wycombe have sold approximately 22,000 tickets for this weekend's play-off final. They will heavily outnumbered by Sunderland supporters, with the Black Cats total allocation standing at 46,460.
It is a remarkable show of support from the fans in north east but where does their away attendance rank compared to Rotherham, Wednesday and Doncaster Rovers?
Below is the average attendance for every League One club and how that compares to their away followings from the 2019-20 campaigns, as supporters were prevented from attending games in 2020-21.
See where your club ranks...