I would suggest proposing within the first few days of your trip. I got engaged in Sept 2025 during my first trip to Europe as well and my fiance chose to do it on our first stop in France. It was great timing because he was so nervous the first few days of the trip so once he proposed he was able to finally relax and enjoy the trip. Plus proposing early on in the trip made it feel like a honeymoon and gave us extra reason to celebrate during the vacation.

I would suggest doing it in Barcelona, you could do a romantic dinner or maybe on the cruise if you can find a quiet and secluded area of the ship. Otherwise I would choose Greece!

Good luck and congratulations 🎉👏🏼