The Solgaleo-GX & Lunala-GX Legendary Starter Set centers around the Legendary Sunne Pokémon Solgaleo and the Legendary Moone Pokémon Lunala, which are featured as Metal-type and Psychic-type Pokémon-GX, respectively. The deck contains an assortment of Pokémon with the same types, as well as some Colorless-type Pokémon, a selection of Trainer cards, and multiples of Energy cards. A handful of these cards, including the focal Pokémon-GX are brand new. The set also includes a rulebook, a player's guide, a coin featuring Cosmog, a playmat, and a cardboard sheet with 42 damage counters, two Special Condition markers, and a GX marker.
Two enhanced versions of this set were also made available on the same day. One of these was the Legendary Starter Set: Premium Edition (Japanese: スターターセット伝説 プレミアムエディション), which includes the main Legendary Starter Set in addition to exclusive Rockruff and Lycanroc SM-P Promotional cards, one pack each of the four dual Sun & Moon Era expansions, and a Solgaleo & Lunala Deck Case. The other enhanced version was the Toys "R" Us Limited GX Battle Starter Special Set (Japanese: トイザらス限定 GX対戦スタータースペシャルセット), which as its name suggests, was only available at Toys "R" Us stores in Japan. The special set contains the main Legendary Starter Set, as well as exclusive Tapu Lele and Tapu Fini SM-P Promotional cards, a Tapu Bulu-GX Enhanced Starter Set, three GX Battle Boost packs, a Solgaleo & Lunala Deck Case, and a Rockruff & Lycanroc Deck Case.