after rival club helsingborg if was relegated from allsvenskan in 1968 (for its first time ever), and after having no success in the qualification to allsvenskan in 1969, the year 1970 became a very important one for landskrona bois. to reach the promotion qualifiers, they had to win at home against helsingborgs if, and so they did, with a single goal scored by the danish player leif carlsen in front of more than 15,000 attenders. in the home game of the qualification for allsvenskan, more than 15,000 attenders came to landskrona ip again, and bois after goals by tommy gustafsson and sonny johansson, won 2–0 against sandvikens if. the away game was played in the northern town luleå, just as the winter began at the 66th latitude. bois managed a goalless draw as result. in the final game, at neutral nya ullevi in gothenburg, bois had to play skövde aik and at least another draw was required for the promotion. it began bad, as skövde scored twice, but by goals from sonny johansson and leif carlsen, landskrona bois finally managed to be promoted back to allsvenskan, after an absence for 21 seasons. as a result of the success, the danish player leif carlsen was forced to leave bois. by 1971, the swedish football association didn't allow foreign players in allsvenskan. during the 1971 season landskrona bois managed to finish on 6th place, but won only 5 games. their home average attendance during the season was 8,504 presumably their best ever (by 2014).