Omniverse is always taking place "now." Ultimate Alien is always taking place just before Omniverse. Alien Force was always taking place "now," until Ultimate Alien aired, at which point it took place about a year ago.
— Dwayne McDuffie's concept of "now", implying the use of a floating timeline. Due to the nature of a floating timeline, the contents and the dates are subject to revision.
Classic timeline is where all of the canon Classic Continuity episodes of take place.
This is the timeline where nearly the entire
Ben 10 series take place. didn't directly happen in this timeline, and Ben 10: Race Against Time and Gwen 10 are "what if" episodes.
Goodbye and Good Riddance
The Universe had been created by the Contemelia and the Slimebiotes started their lifelong mission of seeding life across the growing universe.
The Timeline at the beginning started to branch into many timelines and shift creating its own Timestream.
Realities began to diverge.
Prior to 231AD
Millions of years prior to Omniverse
Azmuth is born.
Zennith is born.
Azmuth creates Primus and later begins creation on Ascalon.
Zennith leaves Azmuth, he doesn't know until he found her gone when he finishes creating Ascalon.
Prior to 1131
Paradox's time machine fails, sending him out of time for 100,000 years.
20th and 21st Century
Fourteen years prior to the original series
Eleven years prior to the original series
Ten years prior to the original series
Seven years prior to the original series
Ten years after Ben 10
Ben loses his childlike glee of being a hero.
Ben mutilates Vilgax.
The Limax War takes place and Max loses his right arm.
The Plutonian Revolt take place, and Ben starts calling himself Ben 10,000 after the war.
Twenty years after Ben 10
Twenty-one years after Ben 10
Twenty-two years after Ben 10
Thirty-two years after Ben 10
The events of take place.
Ken 10 After
Ken 10 4 years after