Heat the oil in a large saucepan over medium heat. Add the onion and cook until softened, about 3 minutes.
Add the garlic, potatoes, and corn and cook for 1 minute.
Add the coconut milk, broth, cumin, coriander, 1 ½ teaspoons salt, and 1/4 teaspoon pepper. Bring to a boil.
Reduce heat and simmer until the potatoes are tender, about 15 minutes.
Add the shrimp and simmer until pink and cooked through, about 3 minutes. Ladle the soup into individual bowls.