Star check-in process
 

As long as I'm at the correct terminal, can I check in for any LH or UA flight at either carrier's check-in counter?

I know you can in some airports, but in all international airports, can I go to either carrier's agent??

Thanks

My experience in most international airports has been that you need to check in with the carrier that you are flying with. There are some exceptions such as OS handling LH check in at VIE, and LH handling OS check in at MUC and FRA. But with UA and LH, I've always had to check in at their respective check-in counters.

Correct. Could become somewhat tricky if codeshare flights are involved. Then usually the carrier operating the flight (or first segment) checks you in.

F.R.

Forgot to mention that for UA check in at FRA or MUC, you have to go through a mini passport check before you enter the line for the actual check in. So you absolutely have to check in at UA counter if you are flying UA metal, code share or not.

You always need to go to the check-in of the operating carrier. In some cases, several airlines use the same counters, but they would then be marked as such. For example, in BRU, LH, OS and now also LX use the same counters. But all three airlines are shown on the screens above the counters (of course LH bigger than OS or LX).