United Airlines has said it will start daily non-stop flights between San Francisco and Singapore's Changi Airport from June 1.

United said in a news release it will be the first airline to offer nonstop service between San Francisco and Singapore, and this will be the only nonstop service to the US from Singapore.

Flying times will be approximately 15 hours, 30 minutes eastbound and 16 hours, 20 minutes westbound.

The Boeing 787-9 Dreamliner will ply the route, United said. At 8,446 miles, the San Francisco-Singapore service will be the longest scheduled 787 flight operated by any airline and the longest scheduled flight operated by any US carrier.

"This long-awaited service has been made possible by the newest version of our customer-pleasing Boeing 787 Dreamliner, and will offer unique benefits to customers traveling between our West Coast hub at San Francisco and Singapore," said Marcel Fuchs, United's vice president of Atlantic and Pacific sales.

"Customers arriving to San Francisco will have dozens of options to connect to other cities across the Americas."

Flight UA1 will depart San Francisco at 11:25 p.m. daily, arriving in Singapore at 6:45 a.m. two days later (all times local). The return flight, UA2, will depart Singapore's Changi Airport at 8:45 a.m. daily, arriving at San Francisco International Airport at 9:15 a.m. the same day.