The Thai Passport is the final item required to access Bangkok. It was released to a small number of players on January 21, 2010.
January 28, 2010 the passport is part of job loot drops in Bangkok.
January 28, 2010 - you can obtain a passport by one of the following
Asking the Clerk once every 12 hours for free
Bribe for 30 RP
Post a news feed stating that you need a passport, and hope someone will gift it to you.
Currently, the most reliable but most costly way to gain a Thai Passport is buying it for 30RP. Though, asking the Clerk can be rather time-consuming but it is free and it is not at all unreliable. The highly recommended way to gain your passport is by asking the Clerk.
from: http://mafiawars.wikia.com/wiki/Thai_Passport