he second Flash, Barry Allen, could travel through time but only by running on a special treadmill. He traveled through time only once on his own after breaking the lightspeed barrier in pursuit of a tachyon that was powering a universe-killing weapon. Upon catching the tachyon and destroying the weapon, he became pure energy and traveled back in time, seeing his entire life rewind before his eyes, and became the very same lightning bolt that gave him his powers in that crime lab accident decades ago.

The other Flashes, Jay Garrick, Wally West, and Bart Allen (formerly Impulse), have not been able to time travel solo.