The tourists won their first series in 16 years at the weekend after a 41-16 victory in Sydney helped them edge out Australia 2-1 during their latest travels.
Howley, having coached Wales during all four of their narrow defeats Down Under in 2012, feels that the Lions' win proves that the home nations can challenge when playing in the Southern Hemisphere.
"The manner of the win on Saturday - 41 points and scoring four tries to one - just shows we can do it," Howley told BBC Sport.
"I've got no doubt, not only from a Welsh perspective, but all the players from England, Scotland and Ireland when they take on the Southern Hemisphere guys again they can go there knowing that they have beaten them," he added.
"The magnitude of [the fact that] we've beaten them over the past three weeks having been there so many times and been so close and yet so far away. And the atmosphere at the stadium was priceless."
Howley picked up 59 caps for Wales during his playing days.