The former political prisoner, who won a seat in parliament in historic April by-elections, is expected to meet the Thai prime minister, attend the World Economic Forum on East Asia and meet Myanmar communities during several days in the country.
Suu Kyi, who spent 15 of the past 22 years under house arrest, will emerge into a world transformed, with the skyscrapers and frenetic activity of Bangkok presenting a stark contrast to her sleepy home city of Yangon, regularly beset by power outages.
She is due to arrive in Bangkok around 14:40 GMT. Her plan to leave Myanmar for the first time since 1988 comes as dramatic changes sweep the country, after decades of outright military rule ended in 2011.
Suu Kyi, fearful that she would never be allowed to return, had refused to travel abroad in the past, even when the former junta denied her dying husband a visa to visit her from Britain.
Migrant workers
Trevor Wilson, a visiting fellow at the Australian National University, said her plans for foreign travel - including a proposed European tour in June - would be a key sign of the changes under a new reformist regime.
"It will demonstrate that the government allows her not only to travel, but also to return to Myanmar afterward and continue her political activities," he said.
Suu Kyi will meet Thai premier Yingluck Shinawatra during her trip, but the timing has not yet to be confirmed, said the prime minister's secretary general Thawat Boonfeung.
Suu Kyi is also set to visit Myanmar migrant workers in Samut Sakhon province, south of Bangkok, on Wednesday according to local activists.
Thailand's workforce is heavily reliant on low-cost foreign workers, both legal and trafficked, with Myanmar nationals accounting for around 80% of the two million registered foreign workers in the country.
Suu Kyi is also expected to travel to the north of the country to meet some of the roughly 100 000 refugees displaced by conflict in Myanmar's eastern border areas.
The Nobel laureate is scheduled to speak in an open discussion with World Economic Forum founder Klaus Schwab and appear at a session on the role of Asian women on Friday.
Nobel Peace Prize
Suu Kyi's European travel plans include an address to an International Labour Organisation conference in Geneva on 14 June.
After that she will make a speech in Oslo on 16 June to finally accept the Nobel Peace Prize she was awarded in 1991 for her peaceful struggle for democracy, according to the Nobel Committee.
She also intends to travel to Britain, where she lived for years with her family, and will address parliament in London on 21 June.
Myanmar President Thein Sein, who is credited with a string of reforms that have prompted the international community to ease sanctions, has postponed his official visit to Thailand, which would have clashed with Suu Kyi's trip.
He will now travel to the country on 4 and 5 June, according to the Thai foreign ministry.