This SFO-NRT business class availability is pricing at 110,000 United MileagePlus miles with minimal fees. The typical rate for this route and cabin runs around 140,000 miles, so you're looking at a savings of roughly 30,000 miles per ticket.
The travel date is August 13, 2026, which falls during peak summer travel season when award space to Japan is particularly hard to find. Only 4 seats are currently showing as available, making this worth a look if you have a family trip in mind and can commit to these dates.
One thing to keep in mind: August in Tokyo means hot and humid weather, but it's also festival season with events like Obon. If you're flexible on your return, book this outbound leg now and search for your return separately.
For families, having 4 seats available on the same flight is notable since business class award space to Japan often appears as just 1 or 2 seats at a time.
How to book
Search and book directly through United's award search tool at united.com. You'll need to log into your MileagePlus account to complete the booking.