Boil the potatoes until tender crisp, about 10 min. Reduce to a simmer, add the garlic to the pot and cook another one to two minutes, until the garlic begins to soften. Drain potatoes and garlic. Transfer to a large bowl or baking dish.
Add the olive oil, rosemary, salt, pepper, and lemon juice to dish and turn to coat potatoes and garlic; let cool.
Thread potatoes and garlic onto four long metal or wooden skewers; grill over medium-high heat, basting occasionally with sauce remaining in dish, about eight minutes or until potatoes are cooked through and skins begin to turn golden.