Under the new policy announced by Qatar Airways and authorities, citizens of 33 mostly European countries can enter without a visa for 90 days in single or multiple trips during a 180-day period.
Americans, Britons, Canadians and citizens of 44 other countries can enter visa-free for an initial 30 days on single or multiple trips, and can extend that for a further 30 days.
Energy-rich Qatar's economy has taken a hit since Saudi Arabia, the United Arab Emirates, Egypt and Bahrain moved to isolate it two months ago over allegations it supports extremists.
The four countries cut diplomatic and transport links with Qatar in June, and barred Qatar from using their airspace and shipping lanes.
In a related development, the UAE and Bahrain today sought to clarify a statement made the day before by the International Civil Aviation Organization, which said both countries had agreed to open up some of their airspace, including new "temporary or contingency" routes, for Qatar Airways.