In a large pot of boiling salted water, cook potatoes until just tender and parboiled, about 3-5 minutes; drain well.
In a small bowl, whisk together olive oil, rosemary, thyme and garlic; season with salt and pepper, to taste. Set aside.
Season steak with Montreal steak seasoning.
Thread potatoes, steak, onion and bell peppers onto skewers; brush with olive oil mixture.
Preheat grill to medium high heat.
Add skewers to grill, and cook, turning occasionally, until the steak is cooked through to desired doneness, about 8-10 minutes.
Serve immediately.
