I am not the biggest fan of Colombian food. I am not a fan at all. So what I can recommend is not going to be local. Although, other types of restaurants in the city were amazing! A lot of tourists come to Cartagena, so the offer is large. Here is there to eat in Cartagena:
Pescadito Cevicheria
This Peruvian place has a large choice of delicious and super fresh ceviches. Try the hot one, served on a stone. It’s to die for.

Address: Cra. 8 ##30-165 a. Map
Cafe Stepping Stone
This is a brunch place, and it’s fantastic! After almost weeks of eating local, I finally arrived to civilization and treated myself with eggs benedict, carrot smoothie, and a latte. It was delicious, well presented and fresh. This cafe has an aircon, which is a very nice change of temperature at midday. They have a strong wifi also, so I recommend it for a break, working space or for a nice brunch.

Address: 30-40 a, Carrera 10 #30102. Map
Casa de la Pasta
It was a discovery of the day. The Italian restaurant that was recommended to us was closed, so we chose another one closeby. And we were very satisfied! Handmade pasta served with a homemade salsa was amazing. Highly recommended for lunch after a night out.

Address: Calle La Magdalena No. 9-67. Map
Novo Kebab Grill
I know, who recommends a Kebab place, right? But honestly, this place was great! Super delicious meat, great service, fresh veggies, and biiig portions. Amazing for a snack in the evening or lunch.

Address: Cl. 39 #9-136, Cartagena. Map
Check out this post about where to go out in Cartagena or that one about the must-see places in the city.