The phrase "regardless when" is grammatically correct and can be used in written English.
For example, "He will come to the party regardless when it is held."
Regardless when he learned about it, Obama is the Commander in Chief.
Regardless, when the race was over, I was a believer in the future of virtual reality.
Regardless, when I called Hotwire and asked for a refund, a rep and his manager refused.
"But I should have known that would have happened regardless when I was coaching the Bulls".
Regardless, when I see this witch hunt against his Administration and Presidency, I will help in any capacity to fight back".
"The fishermen need to earn a living, but we've got to get the stock to recover," says Kerr. "You can't just rob nature regardless when it's critically endangered".
Regardless of when you last bathed your puppy, you will have times when you need to wash immediately.
Regardless of when they strike, don't resist them.
Regardless of when it happens, Bell has been all but gone from the Pirates for days.
The new law treats all celebrities the same, regardless of when they died.
Lebanese officials have said they want all their land restored, regardless of when it was occupied.
