Best European cities for solo travel in your 30s

Hi! I’m 34F planning my first solo trip to Europe for next spring. I’ve always traveled with friends or family and I’m a bit nervous honestly. Looking for cities that feel safe to walk around alone at night, have a great food scene (I’m pescatarian so seafood heavy is a bonus), and where it’s easy to meet other solo travelers without the hostel party scene.

I’m leaning toward Lisbon or Barcelona but also curious about smaller cities I might not have considered. Does anyone have a city that just clicked for them as a solo traveler? Bonus if it’s not insanely expensive.