Hello to everyone.

This is my first time writing in the forum. This spring I will be traveling from SJU to Barcelona with two connections (MIA & LHR). My first portion (from SJU to MIA) will be in a AA flight (no codeshare) then, my connection flights from MIA to LHR and LHR to BCN will be in a British Airways flights. The itinerary was bought through Expedia, and I can see it online in the AA and BA webpage.

I have never made a connection with a different airline, although they are in the same alliance. How will I have to check in? Check in with AA at the airport, then pick up my baggage and check in a again in MIA with BA. Check in with BA or AA online? or just Check in with AA at the airport in SJU and I will be set?

I tried to find the answer but i was unable. I hope you can help me find it!

Thanks!!!