Originally Posted by
alaskaforlife
Is it possible to book an ticket like this?
NRT-SIN-EWR-YVR
The online multi-city doesn't work out
That's a feature, not a bug. The AC website isn't set up to sell legs fully outside of Canada like that (e.g. NRT-SIN).
Are you actually trying to book a one-way NRT-SIN-EWR-YVR? You could certainly price that on Google Flights or Matrix, but going to be hard getting decent pricing doing that all on one ticket and as a one-way.