Taylor Swift -- Go Take a Hike, then Dine on Asian Delight

Taylor Swift hit up Katsuya in Hollywood Monday night without her Calvin ... but she brought along one of her good friends.

Swift and Fifth Harmony singer Camila Cabello chowed down together and left without saying much, but she looks great.

Before dinner ... Taylor went for a hike in L.A., getting some musical inspiration along the way. We doubt her playlist was about Calvin Harris ... too early for that.