With no word if Pelosi will visit the island, she stopped first in Singapore, where Prime Minister Lee Hsien Loong urged her at a meeting to strive for "stable" ties with Beijing.
Her itinerary also includes Malaysia, South Korea and Japan, but a possible Taiwan visit has dominated attention in the run-up.
Reports about a plan to visit the island have enraged Beijing and caused unease in the White House, with President Joe Biden trying to lower the temperature.
Beijing considers self-ruled Taiwan its territory -- to be seized one day, by force if necessary -- and said it would regard a Pelosi visit as a major provocation.
Pelosi's office confirmed her Asia trip in a statement Sunday once her plane was in the air, following days of US media speculation and the speaker refusing to confirm her itinerary.
"The trip will focus on mutual security, economic partnership and democratic governance in the Indo-Pacific region," it said, referring to the Asia-Pacific.
The statement did not mention Taiwan. But visits by US officials there are usually kept secret until delegations land.
And as speculation mounted, both foreign and local media cited unnamed sources Monday to report that Pelosi does indeed plan to include the island on her Asia tour, while the Financial Times said she would meet with President Tsai Ing-wen on Wednesday in Taipe