The 2026 Argentine Primera Nacional, officially known as the Campeonato de Primera Nacional Sur Finanzas 2026 for sponsorship purposes, is the 42nd season of the Primera Nacional, the second-tier competition of Argentine football. Thirty-six teams compete in the league, thirty of which took part in the 2025 season, along with two teams relegated from Liga Profesional, two teams promoted from Torneo Federal A and two teams promoted from Primera B Metropolitana. The fixture draw was held on 22 December 2025, and the season began on 13 February and is scheduled to end in December 2026.
For this season, the competition is played under the same format as the previous season, with the thirty-six participating teams split into two zones of 18 teams, where they will play against the other teams in their group twice: once at home and once away. However, interzonal matches between rival teams will also be played as rival sides were paired together for the season draw and drawn into different zones. Both zone winners will play a final match on neutral ground to decide the first promoted team to the top flight for the following season, while the teams placing from second to eighth place in each zone will play a knockout tournament (Torneo Reducido) for the second promotion berth along with the loser of the final between the zone winners. The bottom two teams from each zone will be relegated to the third-tier leagues, Primera B Metropolitana or Torneo Federal A.
Similar to previous seasons, fifteen Primera Nacional teams will qualify for the following year's Copa Argentina through league performance, those being the top seven teams of each zone plus the best eighth-placed one.
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The interzonal matches will be played on the seventh and twenty-fifth matchdays.