The Dimension Tunnel was first introduced in the last episode of Bakugan Battle Brawlers. Infinity Dragonoid opened up a Dimension Tunnel to Vestroia so all the Bakugan that were on Earth returned home.
Dr. Michael Gehabich also created a Dimension Transporter System that he used to go to Vestroia and to travel between Dimensions. During the first season it broke down and eventually was fixed in Bakugan Battle Brawlers: New Vestroia.
Dan and Drago used one to return to New Vestroia, with Marucho tagging along. They used it again to travel to Spectra's location in episode 44, back to Earth in episode 42 and in episode 51 when they traveled to the Motherpalace.
Anubias and Sellon can also open a Gate but don't use it often. They both used it once to travel to New Vestroia and to summon Chaos Bakugan. Mag Mel also uses something like this but he just teleports to places alongside Anubias and Sellon instead of using a Dimension Gate. Spectra Phantom used it to travel from Vestal to Earth in Interspace Under Siege, but it is unknown how he was able to travel to Bakugan Interspace but it's possible that Infinity Helios summoned a Dimension Gate and traveled there.
In The Prodigal Bakugan, Jaakor, Skytruss, and Orbeum open a Dimension Tunnel to New Vestroia but they don't use it when Jaakor senses Shun is in danger. Later, Skytruss and Orbeum use it to return to New Vestroia.
- According to Dragonoid Colossus, battling in a Dimension Tunnel is a dangerous thing to do. Most likely because it could disrupt the gate and cause the people inside to get stuck between dimensions.