Qantas says it will end direct services to San Francisco a week earlier than initially planned due to aircraft scheduling and passenger demand.
The airline had planned to exit the northern Californian gateway on May 14, before commencing flights to Dallas/Fort Worth in North Texas on May 16.
But the last direct flight to San Francisco will now depart Sydney on May 6.
Qantas spokesperson Emma Kearns said the airline decided to put a week's space between the end of its San Francisco flights and the start of the new service to Dallas/Fort Worth.
"Originally we were going to fly to San Francisco up until 14th but now it is only up until the 6th just due to aircraft scheduling and a decrease in demand on the route," Ms Kearns said.
San Francisco would remain on the Qantas network as a codeshare destination once direct flights cease.
Qantas NSW regional general manager Peter Collins said operating to Dallas gave the airline "unrivalled connections" across North America and Latin America.
"The launch of the route is one of the most important developments for Qantas's international network in many years," Mr Collins said last month.
Dallas Fort Worth Airport (DFW) has put up $US3 million ($A2.85 million) in incentives over two years, representing rebates on landing fees and terminal charges, as well as funding for co-operative marketing initiatives.
The airport said recently the money offered to Qantas was the same as what any airline would receive for starting new services to DFW.
Qantas will fly direct from Sydney to Dallas/Fort Worth - travel time 15 hours and 25 minutes - while the return leg will be via Brisbane using a three-class Boeing 747.
The airline hoped to increase frequency to a daily service in the future and was seeking regulatory approval to co-ordinate with American on areas such as fares, selling activity and joint venture proposals in an expanded commercial relationship.