In the past, I have had no trouble finding China Airlines partner awards on Delta's site, and availability is often wide open. Unfortunately, it looks like Delta's search engine is having trouble seeing that award space these days, for whatever reason. Hopefully this is a situation where you can call in to have a customer service rep book the flight for you; otherwise SkyMiles just got a little bit less useful. Here's China Airlines availability in early February 2018 on ExpertFlyer:
And although I only searched ExpertFlyer for one person, an award itinerary for that date range through Korean Air's site shows a veritable cornucopia of award seats:
However, searching Delta generates one of these two error messages, both of which seem to express shock and surprise that Delta's search engine is a piece of shit. Uh oh! Oh no!
I've tried various cities, different dates, flexible date searches, individual date searches, different cabins, etc and nothing comes up. Maybe I'm doing something wrong and need to go reread the hundreds of tutorials online that cover booking SkyTeam awards on Delta, or maybe the problem is on Delta's end.
Clearly China Airlines isn't blocking award availability to partners, since you can book via Korean. Maybe it would be easier just to do that, but the prices are similar - 80k on Delta the last time I checked (although it might be more now I WOULDN'T KNOW SINCE I CAN'T GET ANY FLIGHTS TO COME UP ONLINE) vs 77,500 on Korean. Problem is, Korean miles are much more valuable and I personally would save them for first class SkyTeam awards, which Delta won't let you book at all. Plus, Korean won't let you book one way partner awards, so you'd need to cough up 155,000 miles for the round trip.
Has anyone else run into this? Are there workarounds I'm not trying? The one thing I am trying is not to hate Delta, but they make it hard sometimes.