Skylanders: Spyro's Adventure was originally going to be an MMORPG known as Spyro's Kingdom. It had the same concept as Skylanders where you can bring your toys to life but Spyro himself was not going to be playable. Instead he was going to be a full-grown dragon and the king of the realm (hence the working title) and what you would do is go to him to receive different quests. The game was also said to be much darker than previous Spyro games including mature themes and even blood which lead to its eventual cancellation and the creation of Skylanders.

The only Skylanders that are referred to by name are Spyro, Trigger Happy and Gill Grunt. This happens only in the first level, Shattered Island.

Most of Sonic Boom's upgrade images show her without her silver armor.

A scrapped version of Camo can be seen in the original game trailer.

An early model for Sunburn shows his figure was to wear a crown, possibly linking him to royalty.

The game was released in Japan almost two years after the initial release in the US. However, instead of being released across a range of different consoles, the game was only released for the Wii and Wii U. Due to this, Japan is the only country with a Wii U release of Spyro's Adventure.

The character design of the water dragon Zap originally began as a snail named "Cyclops Snail". Due to his design resembling other characters, he was redesigned into a new water Skylander without a snail shell named Tarclops. Tarclops was originally planned to appear in the game's starter pack, going so far as having a prototype figurine made, but it was eventually decided that he wasn't fit for the starter pack, and Trigger Happy was chosen instead.

Activision originally wanted to partner with Nintendo and make Skylanders a Nintendo exclusive series. However, Nintendo passed on the offer.

Before settling on “Spyro’s Kingdom”, the game that would eventually become Skylanders: Spyro's Adventure, Toys for Bob experimented with different ideas for the Spyro license. These included a gritty, realistic Spyro, a tiny Spyro that could walk on things like bookshelves, and an origami Spyro.