Sideboard

Tournament Rules section 403 — 14 rules. From Riot's Tournament Rules for sanctioned events, last updated October 9, 2026.

403.1.: In certain competitions, players may have a group of additional cards (outside of their starting configuration) called a sideboard. See 600 for more information on sideboards based on competition formats.
403.2.: Sideboard size and contents are dictated by the competition format.
403.3.: Limits on copies of named cards as defined by competition format apply to the combination of Main Deck and sideboard.
403.4.: Players may use sideboard cards to modify their deck in between games of a match. In constructed, sideboard cards must be exchanged 1 for 1 with Main Deck cards.
403.4.a.: During that time, a player may change their Chosen Champion to one from their sideboard or Main Deck that meets the deckbuilding rules of the competition format.
403.4.b.: In constructed formats, a player may not change their Runes, Legend, or Battlefields at any point after deck registration.
403.4.c.: After the sideboarding process, a player’s Main Deck must meet deck size requirements dictated by the competition format.
403.5.: Players may not use sideboard cards in the first game of a match.
403.6.: Players may count the cards in their opponents’ sideboards at any time.
403.7.: A player may look at their own sideboard at any time, but must keep it distinguishable from other cards.
403.8.: A player’s deck and sideboard must be returned to their registered states before the first game of the next match.
403.9.: If a match completely skips the first game due to a penalty, neither player may sideboard for the following game.
403.10.: If a game ends in a draw, neither player may sideboard for the following game.
403.11.: If a game restarts due to an in-game effect or due to corrective action by judges, the state of each player’s deck and sideboard must remain the same in the restarted game.