In the beginning of the series, Yuma's Deck is filled with the "Syllable" cards, 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. "Full Elf" - "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.Yuma originally played a different Deck. He decided to use his father's Deck in his first Duel against Ryoga Kamishiro. After that Duel, he keeps using this Deck instead of his original one. This Deck was later replaced by a new version after Yuma recieved a large amount of new cards from Rokujuro when he defeated Yamikawa and protected the Duel Lodge.
After his time at the Duel Lodge, Rokujuro gave Yuma the "Duel Lodge secret Deck". According to the former, the Deck is appropriate for Yuma and should answer his feelings. Bronk Stone believes Yuma can improve his Deck with this one for the WDC. Yuma combined elements from both this Deck and his first Deck into a single Deck. He still has access to the "Number" cards. He has also started adding several Xyz anti-support cards to help fight against the "Numbers" which are Xyz Monsters. This Deck also features a large amount of Support Cards for his various "Syllable" archetypes such as "Gagaga" and "Gogogo".
Yuma's Deck is constantly being upgraded by obtaining "Number" cards from various Duelists he faces. When Yuma defeats "Number" holders, Astral absorbs their "Numbers", giving Yuma access to them. Yuma only has access to them while Astral is fighting alongside him in a Duel. So far he collected ten "Numbers". Though he has access to them, he has only played three of the base "Numbers" alongside one upgraded form.