Singapore Airlines’ KrisFlyer program is eyeing the North American market, and in an effort to increase KrisFlyer membership, it’s offering an unprecedented online bonus.

From Aug. 25 to Sept. 30, online roundtrip bookings made through singaporeair.com’s U.S. and Canadian Web sites will earn 10,000 bonus miles for Economy-class (B/Y fares), 20,000 miles for Business Class (C/J fares), and 40,000 miles for First Class (P/F fares). Travel must be completed by Nov. 28. In addition, new members who enroll and activate their account with a mileage-earning fare within the first six months will earn an additional 3,000 miles.

Keeping in mind that international awards start at 15,000 miles (Singapore-Bali), and that a saver award from Hong Kong to San Francisco is 50,000 miles, this is a tremendous value, particularly since the use of the offer is unlimited.

We’ve teased KrisFlyer in the past for being stingy on their bonus offers. We’re happy to stand corrected this time.

Visit http://www.singaporeair.com for details.