The season started on 20 April 2013 and is scheduled to end on 5 October 2013.
A total of 40 teams will contest the league divided into four groups, Eteläinen (Southern), Pohjoinen (Northern), Läntinen (Western) and Itäinen (Eastern).
The bottom two teams in each group and the worst eight-placed will qualify directly for relegation to Kolmonen.
FC POHU, Kerho 07, KäPa, Masku, MuSa, ORPa, PK Keski-Uusimaa, Sudet and Tervarit were promoted from the 2012 Kolmonen.
[1] Warkaus JK was excluded from the Kakkonen due to breaking the rules of the association.