Heat the olive oil in a large pot over medium heat. Add the diced onion and minced garlic. Cook for 3 minutes until the onion softens.
Add the diced bell peppers. Cook for another 4 minutes, stirring occasionally, until the peppers begin to soften.
Stir in the corn kernels, diced potatoes, vegetable broth, and dried thyme. Bring the mixture to a boil, then reduce to a simmer. Cook for 15 minutes until the potatoes are tender.
Use an immersion blender to partially blend the soup in the pot, leaving some chunks for texture. If using a regular blender, transfer half the soup, blend until smooth, and return it to the pot.
Stir in the coconut milk. Season with salt and black pepper to taste. Simmer for 3 more minutes to heat through.
Ladle into bowls and top with chopped parsley if desired.