The leading Nikkei business daily reported that the company has applied to trade its shares in Tokyo and may launch a separate New York listing in a sale that could value it at more than $8 billion.
A Line spokeswoman said the company would not comment on the Nikkei report, which did not cite sources.
Line applied in mid-2014 for a share sale in Japan, and said it was eyeing a US listing as well. But it pulled back in September, saying it needed to focus on growth first some reports said the sale was cancelled due to disagreements with its parent over details of the listing.
The company, which claims more than 400 million registered members in Japan and other parts of Asia, lets users make free calls, send instant messages and post photos or short videos. It combines attributes from Facebook, Skype and WhatsApp.
It reported sales of JPY 86.3 billion ($722 million, roughly Rs. 4,489 crores) in its latest fiscal year.
Best known for letting users send each other cute cartoon "stickers", Line is hugely popular in Japan, particularly among teenagers.
About 88 percent of Japanese smartphone owners use messaging apps such as Line, according to a survey by the Communications and Information network Association of Japan.
Its messaging service was launched in 2011 by the Japanese unit of South Korean Internet service provider Naver Corp. after the quake-tsunami tragedy damaged telecoms infrastructure nationwide, forcing millions of people in Japan to resort to online resources to communicate.
Line is based in Japan, but is owned by Naver.