Cube Sideboards: What Counts as Your Sideboard After the Draft?

TLDR

In a conventional Cube draft using Limited deck-building rules, every card you drafted but did not put into your main deck is part of your sideboard. You can normally change any number of cards between games, and the swaps do not have to be one-for-one, provided your deck still contains at least 40 cards. Basic lands are usually supplied separately. Before the draft, the host should clarify whether decks reset for each new match, how outside-the-game effects work, and whether the event uses any special land-station or sideboarding rules.

The cleanest cube sideboards rules are therefore: your drafted pool belongs to you, your Game 1 deck has at least 40 cards, and everything else you drafted is available between games. That is the Limited-style default, not an unchangeable law for every Cube. Cube is customizable, so an announced house rule can replace the default.

What counts as your Cube sideboard?

Under the Comprehensive Rules framework for individual Limited play, cards in your card pool that are not in your deck form your sideboard. Sideboards are outside the game rather than a zone within the game. Applied to a conventional Cube draft, that means your sideboard consists of the cards you personally drafted but left out of your current deck.

Suppose you drafted 45 cards and built a 40-card deck before adding basic lands. The five drafted cards you did not use are your initial sideboard. If your Cube draft method gives each player 50 or 60 cards, the same principle applies: the size of the sideboard is whatever remains from that player’s drafted pool after deck construction.

Cards drafted by another player, undrafted cards left in the Cube box, tokens, and the rest of the land station are not automatically part of your sideboard. A host can create a different rule, but access should be stated explicitly rather than assumed.

For a broader walkthrough of packs, deck construction, and event setup, see how to run an MTG Cube draft. Players using Winston, Grid, or another small-group method can apply the same card-pool principle, although the number of cards seen and drafted may differ. The comparison of Cube draft formats explains those structural differences.

Default cube sideboards rules at a glance

Question	Limited-style default	Host decision?
What is the sideboard?	Every card in your drafted pool that is not currently in your deck.	The host may define a different pool for unusual formats.
Minimum deck size	At least 40 cards.	A host can announce a different minimum for a custom Cube format.
Number of sideboard cards	No fixed number; it depends on the drafted pool and deck.	The host may impose a cap, but should announce it before drafting.
Changes between games	Any number of cards may move between deck and sideboard.	The host may prohibit sideboarding or use single-game rounds.
One-for-one swaps required?	No, as long as the resulting deck remains legal.	A house rule could require fixed deck and sideboard sizes.
Basic lands	Normally supplied as needed rather than drafted.	The available basic and nonbasic lands are set by the host.
Reset before a new match	Restore the original Game 1 configuration under ordinary tournament policy.	Casual groups may allow continuous construction.
Outside-the-game effects	Use only the player’s drafted sideboard as the safest default.	The host should define access before the event.

How sideboarding works between games

Magic Tournament Rules for Limited use a 40-card minimum and treat opened or drafted cards not included in the deck as the sideboard. Between games, players may exchange cards without making one-for-one swaps, provided the resulting deck still satisfies the minimum.

For example, you could remove three expensive creatures and add two cheap removal spells. Your deck would be one card smaller after the change, but that is legal if it still has at least 40 cards. You could also add three cards without removing anything, producing a 43-card deck. That is legal under the minimum-size rule, although going above 40 generally reduces the chance of drawing your strongest cards.

Sideboarding happens between games, not during a game unless a card specifically creates an applicable effect. In an ordinary best-of-three match, players use their submitted or original build for Game 1, make changes for Game 2, and may change it again for Game 3.

Official tournament policy normally calls for the main deck and sideboard to return to their original compositions before Game 1 against a new opponent, subject to the policy’s continuous-construction provisions. A casual Cube night can instead permit continuous construction, meaning players may keep revising their decks between rounds. Neither approach is inherently better, but mixing them without an announcement creates avoidable confusion.

Official rules, tournament policy, and Cube house rules are different layers

The Comprehensive Rules define concepts such as sideboards and cards outside the game. Tournament Rules govern how organized events handle deck construction, sideboarding, and restoration between matches. The current documents can be found through the official Wizards Play Network rules and documentation page.

A private Cube draft is usually a casual, host-managed play environment rather than a sanctioned Limited event. The official Limited framework is useful because it gives everyone a familiar default, but the Cube owner can change it. The important requirement is procedural clarity: announce the changes before players make draft picks that depend on them.

This distinction matters because sideboard rules alter card value. If there is no sideboarding, a narrow artifact answer must compete for a main-deck slot. If matches are best-of-three with full sideboards, that same answer can be drafted as inexpensive insurance. A rule announced after the draft can therefore invalidate decisions players made in good faith.

Basic lands and the land station

Wizards’ Booster Draft overview describes a 40-card minimum and access to any number of basic lands. Cube groups commonly follow the same broad model by placing basics in a shared land station, but the host controls what that station contains.

Ordinary basics should not need to occupy sideboard slots when the host supplies them freely. Snow-covered basics, Wastes, dual lands, utility lands, and specialty basics are different questions. Do not assume they are freely available merely because they have a land card type. If those cards affect draft incentives, they may need to be drafted or deliberately included in the station.

The host should settle three details before packs are opened:

Which basic lands are freely available?
Are Snow-Covered basics, Wastes, or other specialty lands included?
May players change their basic-land mix between games and matches?

Allowing basic-land changes between games is usually the simplest policy. It lets players support legitimate sideboard changes without requiring them to draft piles of ordinary lands.

How should Wish-style effects work?

Cards that refer to a card “from outside the game” require a clear Cube policy. Because a player’s sideboard is outside the game, the least disruptive default is to let such an effect access only that player’s drafted sideboard. This preserves draft ownership and prevents the card from searching the entire unused Cube.

A host could instead create a shared Wish board, allow access to undrafted cards, or ban outside-the-game access entirely. Those are format-design choices, not automatic extensions of ordinary Cube rules. Broad access can make a Wish substantially stronger and may turn the undrafted portion of a large Cube into an enormous toolbox.

If Wish-style cards are present, announce all three boundaries: which cards can be accessed, whether the cards must have been drafted by that player, and where accessed cards go after use. The answer should be available while drafting because it changes how highly players should pick both the Wish and potential targets.

Which cards are worth drafting for the sideboard?

A good Cube sideboard card solves a matchup that your main deck cannot address efficiently. Its value depends on what the environment supports, how many games each match contains, and how likely you are to face the relevant strategy.

Flexible cards should normally come first. An artifact-removal spell that is also a creature, a graveyard answer with a cycling mode, or a counterspell that remains useful against several archetypes costs less to draft than a card with only one target. Flexibility is especially valuable in smaller drafts, where you see a narrower portion of the Cube and have less information about the field.

More specialized cards become reasonable when the Cube contains enough targets. Useful sideboard roles can include:

Cheap interaction against aggressive decks when your main deck is slow.
Additional threats or card advantage for grindy control matchups.
Artifact and enchantment removal when those permanent types are both common and consequential.
Graveyard interaction when recursion, reanimation, flashback, or similar mechanics have meaningful density.
Countermagic or hand disruption against expensive spells and compact combinations.
Extra removal for resilient creatures or threats that demand a specific answer.
Alternative win conditions when an opponent can neutralize your primary plan.

Avoid spending early picks on extremely narrow answers unless the supported archetype is both powerful and likely to appear. In an eight-player draft, a card that matters against only one possible deck may never leave the sideboard. In a two-player Winston draft, where both players repeatedly face the same opponent, a targeted answer can become much more valuable. See the two-player Winston Draft guide for the format’s information and card-exposure tradeoffs.

A host checklist for sideboard policy

A short announcement before the draft prevents most disputes. The host does not need a tournament packet; the group simply needs consistent answers.

State the minimum deck size and whether there is a maximum.
Define each player’s sideboard as the unused portion of that player’s drafted pool, or explain the alternative.
Announce whether matches are best-of-one, best-of-three, or another structure.
Confirm whether players may make unlimited between-game swaps without one-for-one exchanges.
Say whether decks reset before each new match or use continuous construction.
List the lands available from the shared station.
Explain how outside-the-game and Wish-style effects work.
Identify any cards that use special setup, drafting, or sideboard procedures.

If the group plays single-game rounds, conventional between-game sideboarding will not occur. Sideboard-only cards then lose most of their practical value unless the format uses outside-the-game effects or permits deck rebuilding between opponents. Tell players this before the draft so they can evaluate narrow cards correctly.

The practical default

For most conventional Cube drafts, use the Limited model: build a deck of at least 40 cards, treat every other card you drafted as your sideboard, allow any number of changes between games, and supply ordinary basic lands separately. Reset to the original build before each new match if you want tournament-like consistency; allow continuous construction if the group prefers faster experimentation.

The exact policy matters less than announcing it early. Sideboarding affects draft picks, deck construction, narrow-answer density, and matchup play. Give players the rules before the first pack, then let the Cube’s size, draft method, and match structure determine how much those sideboards matter.