The 20-year-old actress filmed her final scenes as Summer Hoyland last month and will make her on-screen exit in early 2013.
Speaking in a new interview with TV Week, Lucas revealed that her US ambitions were the main factor behind her decision to leave Ramsay Street.
She commented: "I think I'm at the perfect age. Margot Robbie's a good example - she went over at 20 and it just felt like it was the perfect time for her. I think I'm at the age now where I can also go over there and give it a really good shot."
Lucas admitted that she will particularly miss working with Jackie Woodburne and Alan Fletcher, who play Susan and Karl Kennedy.
She said: "I'll really miss Jackie and Fletch. Jackie's the funniest, most down-to-earth woman, and Fletch looked after us all so well. I'll miss everyone - the whole group."
Neighbours airs weekdays at 6.30pm on Eleven in Australia, and weekdays at 1.45pm and 5.30pm on Channel 5 in the UK.