Simulation Bubble is a simulation of the real world in Lyoko created by X.A.N.A. A simulation bubble can be described as a giant bubble that looks much like a Guardian, except that it is completely stationary. The person, or people trapped can freely move around inside the bubble.
They are hemispherical. Like Towers, they seem to emit pulsations, except the pulsations are masked so they cannot be traced back to their source. When Aelita felt pulsations from the first bubble in Ghost Channel, she initially believed X.A.N.A. had activated a Tower she could not locate.
The first time a simulation bubble appeared was in Ghost Channel when X.A.N.A. used it to create a simulation of Kadic and its surrounding area to imprison the Warriors. X.A.N.A. does this to trick them into getting inside of the fake Scanners, so it can delete them for good. When the plan failed, it went for the direct approach to get rid of them with its illusion monsters and wires while they were still trapped, before Aelita dispersed the bubble.
The second time one appeared was in Distant Memory, when X.A.N.A. created a simulation of Franz Hopper's mountain home to imprison Aelita and so X.A.N.A.-William can trap her.
In Temporal Paradox, Tyron had used an armored, metallic version of this technology to trap all of the Lyoko Warriors except for Yumi inside, so that he could use the time reversion program to discover their exact location in the form of calculated time loops.
- It has been shown, but not explicitly stated, that the size of the bubble depends on the size of the virtual structure within, as the bubble in Distant Memory was much smaller than the one that supported Boulogne-Billancourt in Ghost Channel. However, in Evolution, this wouldn't be true as the bubble used by Tyron supported the same location as in Ghost Channel, but it was very small in comparison to the one used in Ghost Channel.
- Each person in any X.A.N.A.-themed bubble has a Blok that controls each them.
- The first bubble was able to hide Ulrich, Odd, and Yumi from scanning via the Factory Interface. The second one wasn't. The third one likewise was able to hide Ulrich, Odd, Aelita and William.