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The 2011 Tercera División play-offs to Segunda División B from Tercera División (Promotion play-offs) were the final playoffs for the promotion from 2010–11 Tercera División to 2011–12 Segunda División B. The first four teams in each group took part in the play-off.
Format
The eighteen group winners had the opportunity to be promoted directly to Segunda División B. The eighteen group winners were drawn into a two-legged series where the nine winners promoted to Segunda División B. The nine losing clubs entered the play-off round for the last nine promotion spots.
The eighteen runners-up were drawn against one of the seventeen fourth-placed clubs outside their group and the eighteen third-placed clubs were drawn against one another in a two-legged series. The twenty-seven winners advanced with the nine losing clubs from the champions' series to determine the eighteen teams that entered the last two-legged series for the last nine promotion spots. In all the playoff series, the lower-ranked club played at home first. Whenever there was a tie in position (e.g. like the group winners in the champions' series or the third-placed teams in the first round), a draw determined the club to play at home first.