In a large bowl, combine soy sauce, brown sugar, olive oil, garlic powder, ground ginger, and black pepper. Whisk until the sugar is dissolved.
Add the ham, pineapple, and bell peppers to the marinade. Toss to coat evenly. Cover and refrigerate for at least 30 minutes to allow the flavors to meld.
Preheat the grill to medium-high heat.
Thread the marinated ham, pineapple, and bell peppers onto the skewers, alternating between each ingredient.
Place the skewers on the grill and cook for about 10-12 minutes, turning occasionally, until the ham is heated through and the pineapple is caramelized.
Remove from the grill and let cool for a few minutes before serving.