Yuma originally uses a Number/Syllable Deck, the "Syllables" being a series of cards which have repetitive names e.g. "Gogogo" (some of his monsters can only be "Syllables" with their Japanese pronunciations, e.g. "Flelf" - "furuerufu"). It is supported with a lot of ATK increasing cards such as "Wonder Wand" and Trap Cards which protect his monsters from destruction such as "Bye Bye Damage". It contains some support for his "Gagaga" monsters later on.
This Deck was later replaced by a new version after Yuma received a large amount of new cards from Roku when he defeated Kaze and protected the Duel Sanctuary.
In the finals of the World Duel Carnival, Yuma debuts more non-"Number" Xyz Monsters, "One-Eyed Skill Gainer" and "Gagaga Cowboy". His WDC profile lists his Deck's name as "Xyz One Turn Kill" as he heavily focuses on using Xyz Monsters and normally wipes out of his opponent's remaining Life Points in the final turn. In addition, as Yuma dealt with more dangerous opponents, he relies heavily on augmenting his "Number C39: Utopia Ray" with abilities of his "ZW -" monsters through the power of ZEXAL than he did before.
Yuma continues to use a Syllable Deck, debuting new "Gagaga", "Gogogo" and "Dododo" monsters, which he primarily uses to Summon "Utopia" in various ways. He supports the cards with Spell and Trap Cards both new and old, including a large amount of Counter Trap Cards. He later modifies this Deck before entering the Sports Duel Tournament hosted at his school. He also makes more use of the vast quantity of "Number" cards that he has at his disposal, though he still favors "Utopia."
Yuma acquires "Number" cards from the various Duelists he confronts. When Yuma defeats "Number" holders, Astral absorbs their "Numbers", giving Yuma access to them. Yuma has access to them while Astral is cooperating with him in a Duel. He can also use them without Astral's presence but only if Astral sends or leaves them to him.
When Dr. Faker used the Sphere Field to steal his "Numbers", Astral is able to eject Yuma from the Sphere Field, giving him "Number 39: Utopia" and "Number 32: Shark Drake" in the process. Yuma returns the latter card to Shark. After Faker and Vector's defeat, Astral absorbed all the "Numbers" from the Sphere Field, with Astral stating that he and Yuma own fifty "Numbers".
In the anime, Yuma has so far collected fifty-four "Numbers", twenty-three of which are unknown.[Notes 52]
In the Aim For Number 1 in the World! non-canon episode, his Deck appears similar to his usual anime Deck, including "Number" monsters. He also Dueled Astral in an explanation Duel at the beginning of the special.
↑Only regular "Numbers" should be counted, meaning no "Number C" members. This is evidenced in episode 22, when Astral mentioned he collected ten cards at that time, but he didn't take "Utopia Ray" into account.